Catholica  Universitas 


Columbia  ©nttier^ttp 

College  of  j^jjpsiicianis  anb  ^urgeonsi 
Hitjrarp 


^ 


THE  LNTERMTMAL  SCIENTIFIC  SERIES, 
VOLUSIE   XXXIX. 


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THE   INTERNATIONAL   SCIENTIFIC  SERIES. 


THE  BEAIN 


AND    ITS   FUNCTIONS. 


BY 

J.    LUYS, 

PHYSICIAN   TO   THE   HOSPICE   DE   LA   SALPETRIEBE. 


?^^\versity  of  ^^^^-jrfff  ILLUSTBATIONS. 


"^  LIBRARY 


^5/^/NGT0^iL5i 


NEW  YORK: 
D.    APPLETON    AND    COMPANY, 

1,   8,    AND   5    BOND     STREET. 
1893. 


\\Q  ^<ic>c 


AUTHOR'S   PREFACE. 


The  present  work,  on  the  structure  and  functions  of 
the  brain,  is  an  abstract  of  my  personal  experience 
as  regards  this  subject,  and  of  most  of  the  ideas  I 
have  for  many  years  been  endeavouring  to  popularize 
in  m.y  public  lectures  at  the  asylum  of  La  Salpetriere. 

It  is  divided  into  two  very  distinct  parts. 

The  first,  anatomical,  serves  as  the  foundation  of 
the  work.  It  is  followed  by  a  second,  purely  physio- 
logical, which  is  its  complement  and  necessary  sequence. 

In  the  first  part  I  have  explained  all  the  technical 
processes  employed  in  arriving  at  the  results  indicated ; 
insisting  at  the  same  time  upon  the  value  of  the  method 
which  I  have  found  it  necessary  to  adopt,  which  consists 
in  making  regularly  stratified  sections  of  the  cerebral 
tissue,  in  the  faithful  reproduction  of  these  by  means 
of  photography,  and  in  the  employment  of  successively 
graduated  powers  for  the  representation  of  certain 
details. 

I  have  been  able,  by  means  of  these  new  methods  of  in- 
vestigation, to  penetrate  further  into  the  still  unexplored 
regions  of  the  nervous  centres,  and,  like  a  traveller 
returned  from  distant  lands,  to  bring  back  correct  views 
and  faithful  representations  of  certain  territories  of 
which  our  predecessors  caught  scarcely  a  glimpse. 


VI  AUTHOR^S  PREFACE. 

Thus,  in  fact,  by  making  this  photo-microscopic 
analysis  of  the  nervous  elements,  I  have  been  able  to 
throw  fresh  light  upon  the  intimate  structure  of  the 
nerve-cell,  and  on  the  organization  of  its  protoplasm, 
and  to  study  it  in  situ,  in  its  connections  with  the  nerve- 
fibres  and  the  surrounding  network  of  neuroglia. 

In  my  explanation  of  the  grouping  of  the  various 
portions  of  the  cerebral  mechanism,  I  have  endeavoured 
as  much  as  possible  to  simplify  their  description,  and 
above  all,  to  avoid  employing  that  strange  vocabulary 
now-a-days  so  improperly  imported  into  the  nomencla- 
ture of  the  different  central  regions  of  the  brain. 

I  have  therefore  sketched  synthetically  the  general 
economy  of  the  structure  of  the  brain,  pointing  out 
the  intimate  relations  which  exist  between  the  cere- 
bral cortex,  the  true  sphere  of  psycho-intellectual 
activity,  and  the  central  ganglions  (those  of  the  optic 
thalami  and  corpora  striata)  which  are  in  a  manner  the 
intermediate  regions  interposed  between  this  and  the 
excitations  which  proceed  from  the  external  world.  I 
have  insisted  on  the  fact,  which  ten  years  ago  I  was 
the  first  in  France  to  bring  to  light,  namely,  that  the 
optic  thalamus,  with  the  isolated  grey  ganglions  of 
which  it  is  composed,  represents  a  place  of  passage  and 
reinforcement  for  excitations  radiated  from  the  sensorial 
periphery,  while  the  corpus  striatum,  with  its  different 
compartments,  and  arches  one  within  another,  is  on  the 
contrary  directly  related  to  the  passage  of  voluntary- 
motor  excitations. 

In  this  anatomical  part  I  have  particularly  emphasized 
those  details  of  the  essential  structure  of  the  cerebral 
cortex,  to  the  existence  of  which  sufficient  attention  has 


AUTHOR  S   PREFACE.  Vll 

not  as  yet  been  paid,  and  have  utilized  them  from  the 
stand-point  of  physiological  interpretation. 

Thus,  having-  established  the  presence  in  the  cerebral 
cortex  of  special  zones  of  small  cells  subjacent  to  the 
pia-mater,  and  quite  different  in  configuration  from  the 
zones  of  large  cells  occupying  the  deeper  regions,  I 
was  led  to  see  in  this  anatomical  arrangement  a  clear 
relationship  to  a  similar  disposition  existing  m  the 
constitution  of  the  grey  axis  of  the  spinal  cord. 

As  a  consequence,  I  was  led  to  think  that  if,  as  is 
experimentally  demonstrated,  the  small  elements  in 
the  spinal  cord  be  affected  by  the  phenomena  of 
sensibility,  it  was  natural  to  admit  physiological 
analogies  where  jnorpJiological  analogies  exist  ;  and 
consequently  to  consider  the  sub-meningeal  regions 
of  the  cerebral  cortex  as  being  the  histological 
territory  specially  reserved  for  the  dissemination  of 
sensible  impressions  ;  while  the  deeper  zones  of  large 
cells  (analogous  to  the  ant-^rior  m.otor  columns  of  the 
cord)  might  be  considered  as  the  regions  of  emis- 
sion (psycho-mptor  centres)  for  exciting  voluntary 
motion.  Thus,  I  arrived  at  the  demonstration  that, 
in  the  very  structure  of  the  cerebral  cortex,  among  the 
thousands  of  elements  of  which  it  is  composed,  there 
is  an  entire  series  of  special  nerve  cells,  intimately 
connected  one  with  another,  constituting  perfectly 
defined  zones,  anatomically  appreciable,  and  serving 
as  a  common  reservoir  for  all  the  diffuse  sensibilities  of 
the  organism,  which,  as  they  are  successiv^ely  absorbed 
in  these  tissues,  produce  in  this  region  of  the  sensoriiiin 
co7nniiine  that  series  of  impressions  which  brings  with 
it  movement  and  life. 


viil  AUTHOR  S  PREFACE. 

In  the  second  part,  which  comprises  an  explanation 
of  the  uses  of  the  different  cerebral  apparatuses  of 
which  the  anatomical  details  have  been  previously 
analyzed,  I  have  in  the  first  place  given  a  physiological 
explanation  of  the  different  fundamental  properties  of 
the  nervous  elements,  considered  as  .living  histological 
units. 

I  have  in  this  manner  shewn  that  these  properties, 
which  are  the  ultimate  generating  elements  of  all 
the  forms  of  activity  of  cerebral  life,  may  be  finally 
reduced  to  three  principal  forms : — sensibility,  by  virtue 
of  which  the  cerebral  cell  enters  into  relation  with  the 
surrounding  medium  ;  organic  phosphorescence,  which 
confers  upon  it  the  property  of  storing  up  in  itself  and 
retaining  the  sensorial  vibrations  which  have  previously 
excited  it  (as  we  see  in  the  inorganic  world  phospho- 
rescent bodies  preserve  for  a  longer  or  shorter  period 
traces  of  the  luminous  vibrations  which  have  impinged 
upon  them)  ;  automatism,  which  is  merely  the  aptitude 
which  the  nerve-cell  possesses,  for  reacting  in  presence 
of  the  surrounding  medium,  when  once  it  has  been 
impressed  by  this. 

Having  thus  surveyed  each  of  these  elementary  pro- 
perties of  the  nervous  elements  in  their  origin,  in  their 
evolution  throughout  the  organism,  in  their  normal  mani- 
festation and  pathological  deviation,  I  arrive  at  the 
demonstration  that  it  is  by  means  of  their  combination, 
and  by  the  harmonious  co-ordniation  of  all  their  truly 
specific  energies,  that  the  brain  feels,  remembers,  and 
reacts  ;  and  that,  in  fact,  being  the  properties  in  which  all 
the  others  originate,  they  are  the  only  living  forces  that 
are  always  present,  always  underlying  the  infinite  series 


author's  preface.  ix 

of  operations  which  it  every  moment  accomphshes  ;  and 
that  without  them  that  admirable  and  complex  appa- 
ratus, at  once  so  delicate  and  so  simple,  would  be  as 
absolutely  without  life  and  without  movement,  as  the 
earth  would  be  without  the  sun. 

Having  thus  examined  the  elementary  properties  of 
the  nervous  elements,  I  have  shewn  how  their  co- 
operation may  be  used  to  explain  the  principal 
phenomena  of  cerebral  physiology. 

I  have  in  this  manner  made  it  clear  that  by  group- 
ing among  themselves  the  foregoing  data,  we  may 
perceive  that  all  manifestations  of  cerebral  activity — 
even  though  we  have  to  deal  with  the  phenomena  of 
psychical  life  proper,  or  the  operations  of  intellectual 
life,— like  their  fellows  which  have  the  spinal  cord  for  a 
theatre  (reflex  phenomena)  are  always  susceptible  of 
being  decomposed  into  three  elementary  phases  ;  that 
they  are  always  originally  determined  by  the  arrival  of 
an  incident  sensorial  impression,  recent  or  former  (phase 
of  incidence) ;  accelerated  by  the  particular  reaction 
of  the  interposed  medium,  reacting  by  virtue  of  its 
specific  energy  (intermediate  phase)  ;  and  completed  by 
the  secondary  reaction  of  the  intermediate  medium, 
reacting  and  carrying  outwards  the  primordial  vibration 
which  has  been  communicated  to  it  (phase  of  re- 
flexion). 

It  results,  then,  from  this  manner  of  looking  at  the 
phenomena  of  cerebral  activity,  that 'it  is  always  a  fact 
of  the  vital  order  which  is  at  the  origin  of  every  process 
in  evolution.  Sensibility  is  always  the  primary  motor 
agent ;  it  originates  all  movement.  Propagated  through 
the  sensori-motor  machinery  of  the  cortex,  it  becomes 


X  AUTHOR  S   PREFACE. 

insensibly  transformed,  like  a  force  in  evolution,  and 
ends  by  disengaging  itself  from  the  organism  in  the 
form  of  a  motor  act 

In  short,  in  these  researches,  in  which  my  sole  object 
has  been  to  carry  the  data  of  contemporary  physiology 
into  the  hitherto  uninvaded  domain  of  speculative  psy- 
chology, I  have  endeavoured  to  show  that  the  most 
complex  acts  of  psycho-intellectual  activity  are  all  defi- 
nitely resolvable,  by  the  analysis  of  nervous  activity,  into 
regular  processes  ;  that  they  obey  regular  laws  of  evolu- 
tion; that,  like  all  their  organic  fellows,  they  are  capable 
of  being  interrupted  or  disturbed  in  their  manifestations 
by  dislocations  occurring  in  the  essential  structure  of  the 
organic  substratum  which  supports  them  ;  and  that,  in  a 
word,  there  is  from  this  time  forth  a  true  physiology  of 
the  brain,  as  legitimately  established,  as  legitimately  con- 
stituted, as  that  of  the  heart,  lungs,  or  muscular  system. 

As  a  consequence  of  what  has  just  been  said,  it  neces- 
sarily follows  that  this  range  of  studies,  so  new  and  so 
attractive,  should  properly  belong  to  the  physiological 
physician  and  to  him  alone.  Henceforward  he  may 
claim  as  his  peculiar  patrimony  that  special  domain  of 
the  nature  of  man  concerning  which  speculative  phi- 
losophy has  for  so  many  centuries  so  long  and  learnedly 
harangued.  It  will  be  his  task  to  fertilize  it  by  his 
incessant  labour,  and  to  make  it  yield  what  all  labour 
intelligently  directed  should  afford,  legitimate  fruits — 
practical  consequences  which  may  be  utilized  for  the 
benefit  of  suffering  humanity.  The  history  of  medical 
science  is  present  with  its  daily  lessons,  to  shew  us 
that  the  useful  acquisitions  which  it  has  made  have 
always  been  inevitably  subordinated  to  clearer  and  more 


author's  preface.  xi 

precise  notions  concerning  the  anatomy  of  the  organs 
whose  care  is  its  mission  ;  and  when  we  transfer  the 
same  aspirations  to  the  subject  which  now  occupies  us, 
this  fact  surely  authorizes  us  to  hope  that  in  the  future 
we  shall  see  new  methods  in  the  treatment  of  mental 
maladies,  and  modes  of  action  more  efficacious  than 
those  now  at  our  disposal,  arise  from  a  better  compre- 
hended cerebral  anatomy,  and  a  more  rationally  directed 
cerebral  physiology. 

J.  LUYS. 


CONTENT  S. 


pAca 
Preface        ••••••••••••v 


PART    L 

ANATOMY   OF   THE    BRAIN. 


CHAPTER    I. 
Methods  of  Study •       •       •       •       i 


CHAPTER    II. 
Cortex  of  the  ERArN— The  Grey  Cortical  Substance      •       ,      ix 

CHAPTER    HI. 
The  White  Substanxe  of  the  Brain     ......      26 


CHAPTER    IV. 
The  Optic  Thalamus 34 


CHAPTER  V. 
The  Corpus  Striatum .      46 


CH.IPTER   VI. 
Physiological  Deductions 59 

2 


XIV  CONTENTS. 


CHAPTER    VII. 

PAGB 

Physico-ChExMical  Phenomena  of  Cerebral  Activity         .        .      68 


PART   IL 

GENERAL    PROPERTIES    OF   THE    NERVOUS    ELEMENTS. 


BOOK   I. 

SENSIBILITY   OF    THE    NERVOUS    ELEMENTS. 


CHAPTER   I. 

Graduation    and    Genealogy    of    thf.    Phenomena    of    Sensi- 
bility        83 

CHAPTER   II. 

Evolution  of  the  Process  of  Sensibility  through  the  Me- 
chanism OF  THE  Nervous  System — Unconscious  Sensibility 
— Conscious  Sensibility  (Sensation) 91 

CHAPTER    III. 
Intra-Cerebral  Propagation  of  the  Processes  of  Sensibility    102 

CHAPTER   IV. 

r»ERTURBATIONS   OF   SENSIBILITY    ..«•••••      II4 

CHAPTER    V. 
Dlvelopment  of  Sensibility     ....•«.■     ta6 


CONTENTS.  XV 

BOOK   11. 

ORGANIC  PHOSPHORESCENCE  OF  THE  NERVOUS  ELEMENTS. 


CHAPTER    I. 

PAGB 
INTRODUCTORY  ,,,. 133 


CHAPTER    II. 
Genesis  and  Evolution  of  Memory 142 

CHAPTER    HI. 
The  Memory  in  Exercise •       •        .    150 

CHAPTER    IV. 
Development  of  the  Phenomena  of  Memory     .        •        •        .      159 

CHAPTER   V. 
Functional  Disturbances  of  the  Phenomena  of  Memory       .    165 


BOOK    TIT. 

AUTOMATIC   ACTIVITY   OF   THE    NERVOUS   ELEMENTS. 


CHAPTER    I. 
Inteoductory       ••••.••••••171 


xvi  CONTENTS. 


CHAPTER   II. 
Genesis  and  Evolution  of  Automatic  Activity  .       .       •       .176 


CHAPTER    HI. 
Automatism  in  Psycho-Intellectual  Activity    .       •       •       .    180 


CHAPTER    IV. 
Dreams 195 


CHAPTER   V. 
Development  of  Automatic  Activity     .       •       •       .       .    •.    200 


CHAPTER   VI. 
Functional  Perturbations  of  Automatic  Activity    .       .       .    ^05 


PART   III, 

EVOLUTION    OF   THi:   PROCESSES   OF   CEREBRAL   ACTIVITY. 


BOOK    I. 


PHASE    OF    INCIDENCE   OF  THE    PROCESSES   OF    CEREBRAL 

ACTIVITY. 


CHAPTER    I. 
Attention ,.        .•••    215 


CONTENTS.  XVIJ 


CHAPTER    II. 

PAGE 

Constitution  ok  the  Sphere  of  Psycho-Intellectual  Activity    226 


CHAPTER   III. 
Genesis  of  the  Notion  of  Personality         .....    233 

CHAPTER   IV. 
Development  of  the  Notion  of  Personality      ....    238 

CHAPTER   V. 
Functional  Disturbance  of  the  Notion  of  Personality         .    244 


BOOK   II. 

PHASE  OF    PROPAGATION  OF  THE  PROCESSES  OF  CEREBRAL 

ACTIVITY. 


CHAPTER   I. 

Dissemination  of  Sensorial   Impressions  in  the  Plexuses  of 

the  Psycho-Intellectual  Sphere — Glnesis  of  Ideas  .        .    250 

CHAPTER   11. 
Evolution  and  Transformation  of  Sensorial  Impressions    .    256 

CHAPTER    III. 
The  Judgment      • »•,    2S9 


xviii  CONTENTS. 


BOOK    III. 


PHASE   OF   REFLEXION    OR    EMISSION    OF   THE   PROCESSES 
OF    CEREBRAL   ACIIVITY. 


CHAPTER    I. 

PAGE 

Reflexion  of  Motor  Processes  upon  the  Phenomena  of  Vege- 
tative Life 313 


CHAPTER    n. 

True  Period  of  Emission  of  the  Processes  which  produce 
Voluntary  Motion  —  Spontaneous  Reaction  of  the 
Sensorjum-— Motived  Resolution      •••«».*  315 


LIST   OF    ILLUSTRATIONS. 


PAGE 

Fig.  I. — Diagram  of  a  Section  of  the  Cerebral  Cortex   .        .    15 

Fig.  2. — Cortical  Cell  of  the  Deeper  Zones         .        .        .        .19 

Fig.  3. — Diagram    of    Commissural    Fibres    of    the    Anterior 

Regions   of  the   Brain 27 

Fig.  4..  — Diagram  of  Commissural  Fibres  on  the  level  of  the 

Corpus  Striatum .29 

Fig.  5. — Diagram  of  Converging  Fibres,  and  their  Relations 

with  the  Central  Grey  Ganglions     .        .        .        .31 

Fig.  6. — Diagram  of  the  Sensori-Motor  Processes  of  Cerebral 

Activity     ••••••••       ..di 


THE    BRAIN. 

PART  I. 

ANATOMY    OF    THE    BRAIN. 


CHAPTER    I. 

METHODS  OF   STUDY. 

The  study  of  the  nervous  centres  has  always  strongly 
attracted  the  anatomist  as  a  field  of  labour ;  and  the 
reason  of  this  is  not  far  to  seek.  In  the  face  of  such  a 
subject,  not  only  does  the  very  natural  desire  to  pene- 
trate the  inmost  secrets  of  the  organization  of  the  anato- 
mical details  under  consideration  come  into  play,  but, 
further,  there  is  that  unconscious  attraction  which  draws 
the  human  mind  towards  the  unexplored  regions  of  the 
unknown — towards  those  mysterious  realms  where  the 
living  forces  of  all  our  mental  activities  are  silently 
elaborated,  and  where  the  solution  of  those  eternal 
problems,  regarding  the  relations  of  the  physical  organi- 
zation of  the  living  being  to  the  acts  of  its  psychic  and 
intellectual  life,  evades  us  as  we  pursue  it. 


2  THE  BRAIN   AND   ITS   FUNCTIONS. 

Hence  it  is  that  from  century  to  century  most  of  the 
great  anatomists  have,  each  in  his  turn,  laboured  in  this 
direction.  Hence  Galen,  Varolius,  Willis,  Malpighi, 
Vieussens,  Vicq  d'Azyr,  Sommering,  Reil,  etc.,  have 
successively,  in  their  immortal  works,  either  described 
the  organization  of  the  nervous  centres  as  they  conceived 
of  it  at  their  own  epoch,  or  expressed  in  their  icono- 
graphies (with  a  more  or  less  distinct  glimpse  of  the 
truth)  the  objective  fashion  in  which  they  saw  the 
anatomical  details  they  have  successively  represented. 

In  dealing  with  a  subject  so  vast  and  so  delicate,  and 
a  material  so  fragile  and  easily  alterable  as  the  nervous 
matter,  the  student  is  necessarily  forced  to  depend  on 
the  different  methods  placed  at  his  disposal  by  the 
arts  and  sciences  of  his  own  epoch.  Hence  the  smallest 
technical  discoveries  frequently  become  of  inestimable 
value  ;  and  it  may  be  said,  without  exaggeration,  that 
the  utilization  of  chromic  acid,*  which,  by  hardening 
the  nerve-substance,  fixes  it,  with  all  its  natural 
relations,  without  altering  it,  has  been  one  of  those  new 
methods  in  laboratory  work  which  have  most  essentially 
contributed  to  the  success  of  those  great  achievements 
in  this  particular  domain  of  anatomical  science  which 
our  own  century  has  witnessed. 

On  the  other  hand,  the  perfecting  of  the  magni- 
(ylng  power  of  microscopes  has  been  of  immense  service, 
and  has  permitted  the  spirit  of  man  to  advance  with 
vast  strides  into  regions  as  yet  unexplored,  where 
it  stands  face  to  face  with  those  ultimate  anatomical 
units,  the  nerve-cells,  of  which  our  predecessors  scarcely 

*  Hannovor,  in  1840,  was  the  first  to  point  out  the  hardening  properties  of 
chromic  acid.     (Robin,  Traite  du  microscope,  p.  297.    J.  B.  Bailliere,  1871.) 


METHODS   iDF   STUDY.  3 

caught  a  glimpse.  Thus  it  is  now  possible  to  give  exact 
descriptions  of  their  configuration,  whether  we  study 
their  connections,  their  minute  structure,  or  the  different 
pathological  deviations  they  may  undergo. 

The  introduction  of  the  microscope  into  the  study  of 
histology  has  been  in  our  century  for  the  world  of  the 
infinitely  Httle,  what  at  another  period  of  human 
development  the  intervention  of  the  telescope  was  for 
the  exploration  of  the  sidereal  world.  It  has  rendered 
distinctly  visible  all  those  myriads  of  elements  which, 
from  their  extreme  smallness,  were  concealed  from  the 
eyes  of  our  predecessors.  It  has  brought  them  to 
light,  revealed  the  secrets  of  their  minute  organization, 
and  opened  to  the  investigations  of  anatomists  an  entire 
new  world  of  unexpected  ideas. 

Following  upon  this  discovery,  as  a  natural  conse- 
quence, came  the  revelation  of  the  art — previously  un- 
known in  our  laboratories — of  makinsf  thin  slices  of 
nervous  tissue,  colouring  them,  rendering  them  trans- 
parent, and  preserving  them.  The  employment  of 
reagents  of  all  kinds,  which,  testing  in  some  degree  the 
special  sensibility  of  each  histological  element,  colours 
it  in  a  particular  manner,  and  sets  in  relief  the  pecu- 
liarities of  its  structure,  has  opened  a  new  road  for 
progress  ;  so  that  all  over  the  civilized  world,  labourers, 
aided  by  physics  and  chemistry,  have  united  their  efforts, 
until  we  can  say  that  the  limits  of  the  unknown  recede, 
and  that  new  conquests  are  perpetually  being  registered 
in  our  scientific  reports. 

But  this  is  not  all.  In  this  kind  of  research  it  is 
not  sufficient  to  see  for  ourselves  the  new  facts  met  with 
on  our  road  ;  it  is  necessary  to  make  others  see  them, 


4  THE  BRAIN   AND  ITS   FUNCTIONS. 

to  represent  in  faithful  statements  the  details  of  nature 
we  have  examined,  and  to  place  the  newly-registered 
facts  beyond  dispute. 

Up  to  the  present  time  it  was  the  observer  himself 
who  pourtrayed,  by  means  of  his  pencil,  the  objects 
which  passed  through  the  focus  of  his  microscope.  And, 
accordingly,  we  all  know  how  widely  these  nominal 
drawings — even  those  made  by  masters  of  their  pro- 
fession— usually  diverge  from  the  truth  ;  simply  because 
they  can  never  express  more  than  those  details  which  the 
artist  has  perceived  and  recognized,  and  a  species  oi 
unconscious  selection  from  the  objects  which  are  passing 
before  his  eyes.  It  is,  then,  in  presence  of  these  deside- 
rata, as  regards  graphic  representation,  in  drawings  made 
by  hand  that  we  feel  the  necessity  of  applying  the 
marvellous  resources  now  oftered  us  by  photography  to 
the  reproduction  of  microscopic  objects. 

The  sensitized  plate  henceforward  plays  its  part  in 
the  world  of  scientific  investigation,  in  the  study  of  the 
phenomena  that  occur  in  the  world  of  the  infinitely 
little,  as  well  as  in  the  study  of  those  that  occur  in  the 
world  of  the  infinitely  great — registering  histological 
facts  as  well  as  astronomical  phenomena,  and  thus 
becoming  the  impersonal  and  automatic  pourtrayer  of 
the  most  minute  details  that  have  impressed  themselves 
upon  it.  Thus,  wonderful  to  relate,  photography,  very 
much  superior  to  drawing,  not  only  reveals  the  objects 
which  the  eye  perceives,  but  brings  to  light  in  addition 
a  whole  series  of  latent  details,  which  await  but  the 
intervention  of  a  simple  lens  to  be  successively  recog- 
nized upon  the  prints  when  obtained. 

These  new  means  of  investigation,  which  the  scien- 


METHODS   OF  STUDY.  5 

tific  methods  of  the  nineteenth  century  have  placed 
within  the  reach  of  our  generation,  will,  therefore, 
explain  the  progress  accomplished,  and  show  us  once 
more  that,  in  the  long  process  of  evolution  which  extends 
through  ages,  man  only  arrives  step  by  step  at  the 
fragments  of  truth  which  he  snatches,  and  that  even  his 
most  persevering  efforts  only  serve  to  cause  the  unknown 
to  recede  a  few  paces  backwards.  It  is  strange  to  find 
that,  as  fast  as  any  progress  is  accomplished  and  new 
discoveries  registered,  new  problems  incessantly  start 
up  ;  and  that  just  when  we  thought  we  had  arrived  at 
the  utmost  limits  of  the  known  world,  at  the  demon- 
stration of  elements,  simple,  fixed,  definite,  our  perfected 
methods  of  study  enable  us  to  see  new  complexities 
and  unexpected  horizons. 

Thus,  for  instance,  by  means  of  high  powers,  the 
histological  elements  of  the  nerve-cell,  hitherto  con- 
sidered as  the  primordial  and  irreducible  units  of  the 
system,  become  themselves  divisible  into  secondary 
elements. 

Photo-chemical  histology,  indeed,  shows  us  that  the 
protoplasm  of  the  cell,  formerly  described  as  a  homo- 
geneous substance,  is  arranged  in  a  fibrillary  trellis-work ; 
that  its  nucleus  presents  an  arrangement  of  radiated 
fibres  ;  and  that  what  was  thought  to  be  the  nucleolus  is 
itself  a  complex  element.  The  nerve-cell  thus  becomes 
in  its  turn  a  little  nervous  organ  sui  generis,  {See  Fig.  2.) 

The  same  analytic  processes  enable  us,  moreover,  to 
demonstrate  that  the  network,  so  dense  and  compact, 
which  unites  all  the  nerve-cells  of  the  cerebral  cortex, 
for  instance,  one  with  another,  is  so  delicate  that,  when 
enlarged  to   2S5  diameters,   the  fibres   of    which  it  is 


6  THE   BRAIN   AND   ITS   FUNCTIONS. 

composed  become  visible,  like  single  hairs  in  appearance 
and  magnitude,  etc. 

Wliat  will  be  the  end  of  these  unforeseen  details 
which  present  themselves  in  the  train  of  each  adap- 
tation of  a  new  method  of  study,  to  our  researches 
into  the  nervous  system  ? 

No  one  knows  as  yet.  It  seems  as  though  the 
secrets  of  nervous  organization  escape  from  our  eyes 
as  fast  as  we  press  further  into  the  regions  where  they 
conceal  themselves,  and  while  anticipating  the  new 
methods  of  analysis  which  the  future  holds  in  reserve, 
we  cannot  help  thinking  that  there  is  still  much  to  do, 
and  that  now,  more  than  ever,  we  should  remenrber 
that  true  saying  of  Serres :  **  We  have  been  dissecting 
the  brain  since  Galen's  time,  yet  there  is  not  an 
anatomist  who  has  not  left  his  successors  something 
to  do." 

The  labours  of  which  I  am  about  to  give  a  restnn^y 
are,  then,  but  one  of  the  phases  of  this  long  discussion 
concerning  the  structure  of  the  nervous  centres  which 
has  been  going  on  for  centuries. 

If  they  do  not  establish  the  truth  absolutely  and 
finally,  they  will  at  least  have  the  merit  of  being  the 
result  of  contemporary  science,  and  a  sort  of  synthesis 
of  the  methods  of  work  at  our  disposal. 

The  method  I  have  employed  for  studying  the 
organization  of  the  cerebro-spinal  centre  in  man,  I  have 
already  explained  in  my  first  work.*  It  essentially 
consists  in  the  preparation  of  a  series  of  sections  made 
methodically,  millimetre  hy  millimetre,  vertically,  hori- 

*  J.  Luys,  "  Recherches  sur  ranatomie.  la  physiologic  et  la  pathologie  du 
systenie  nerveux."     Paris,  1865,  J.  B.  Bailliere. 


METHODS   OF   STUDY.  7 

zontally,  and  antero-posterlorly ;  and — these  sections 
being  thus  made  according  to  the  three  dimensions  of 
the  soHd  mass  which  was  to  be  studied — in  reproducing 
them  all  photographically. 

I  set  myself,  then,  to  make  a  series  of  successive 
horizontal  sections  of  the  brain,  previously  hardened  in 
a  chromic  acid  solution,  from  apex  to  base,  at  intervals 
of  about  one  millimetre,  and  as  perfect  as  possible ; 
each  being  in  its  turn  reproduced  by  photography. 

I  made  similar  sections  of  the  brain  in  a  vertical 
and  antero-posterior  direction,  and  at  regular  intervals 
from  behind  forwards. 

These  operations  having  been  thus  regularly  con- 
ducted, this  method  enabled  me  to  have  representations 
of  the  reality  as  exact  as  possible  ;  to  keep  the  natural 
relations  of  the  most  delicate  portions  of  the  nervous 
centres  each  by  each,  according  to  their  normal  connec- 
tions, and,  in  fact,  without  deranging  anything.  Thus 
by  comparing  the  sections,  horizontal  or  vertical,  one 
with  another,  I  could  follow  a  given  order  of  nerve- 
fibres  in  its  progress,  see  its  point  of  origin,  and  its 
point  of  termination  ;  study  the  natural  increase  in  com- 
plexity of  the  different  kinds  of  nerve  fibrils,  millimetre 
by  millimetre,  changing  nothing,  lacerating  nothing, 
and  leaving  everything  pretty  much  in  its  normal 
position.* 

*  The  plan  of  this  work  does  not  permit  me  to  insist  upon  the  innumerable 
difificulties  I  have  surmounted,  in  arriving  at  the  clear  result  already  recorded 
in  my  photographic  iconography.  (Luys,  "  Iconographie  des  centres  nerveux," 
J.  B.  Bailli^re,  Paris,  1872.) 

In  the  first  place  I  had  to  invent  cutting  instruments  sufBciently  delicate  to 
make  complete  sections  of  the  brain,  of  the  thickness  of  about  one  millimetre. 

But  these  pieces,  when  sufficiently  hardened  to  undergo  the  action  of  the 
cutting  instrument,  had  acquired,  on  coming  out  of  the  bath  of  chromic  acid, 


8  THE  BRAIN  AND   ITS  FUNCTIONS. 

By  means  of  these  new  photographic  methods  o{ 
reproduction,  which  are  all  the  more  precise  because 
impersonal,  I  had  only,  then,  to  register  the  details  the 
sun  himself  had  printed,  to  place  the  prints  in  juxta- 
position, to  compare  them  one  with  another,  and  thus 
to  make  a  single  synthesis  of  the  multiple  elements  of 
analysis  I  had  thus  obtained  by  the  automatic  co-opera- 
tion of  the  light. 

The  general  view  of  cerebral  topography  having  thus 
been  fixed  by  these  processes,  the  regions  of  more 
delicate  texture,  the  special  points  which  it  was  necessary 
to  study  in  their  minute  elements,  were  further  suffi- 
ciently magnified  and  reproduced,  with  successively  in- 
creasing powers.  I  could  thus  render  visible  to  the 
naked  eye,  and  exhibit  on  a  plan,  details  of  structure 
which,  up  to  that  time,  had  only  been  seen  in  isolation 
under  the  tube  of  the  microscope.  By  this  means  the 
mind  of  the  observer,  penetrating  successively  from  the 
known  to  the  unknown,  from  well-defined  regions  to 
those  which  are  not  so  as  yet,  can  easily  make  itself 
familiar  with  the  details  of  the  minute  structure  of  the 
final  nerve  elements. 

The  cerebro-spinal  system  in  man  and  the  vertebrates 
consists  of  three  departments,  independent  one  of 
another,  and  yet  very  intimately  connected.  These 
are: — 

I.  The  cerebrum  proper. 

that  peculiar  uniform  greenish  colouring  which  renders  them  completely  unfit 
for  photogenic  action.  It  was  therefore  necessary  to  discover  a  perfectly  novel 
series  of  processes,  in  order  to  purify  the  >e  sections  from  the  chromic  acid, 
and,  without  altering  them,  to  impart  to  them  photogenic  properties.  (See 
Journal  d'Anatojme  de  Robin,  Paris,  1872,  for  the  whole  series  of  the  pro- 
cesses emploved  to  bleach  the  sections  tinted  with  chromic  acid.) 


METHODS  OF   STUDY.  9 

2.  The  cerebellum  and  the  apparatuses  of  cerebellar 
innervation  annexed  thereto. 

3.  The  medidla  spinalis  and  its  encephalic  expansions. 
In   this   study  we   shall    occupy  ourselves  with  the 

cerebrum  proper  only. 

The  cerebrum  consists  of  two  lobes  or  hemispheres 
united  to  one  another  by  a  series  of  white  transverse 
fibres,  which  form  an  anastomosis  between  the  homo-  ^ 
logons  regions  of  each  lobe,  so  as  to  constitute  a  twin 
system,  of  which  all  the  molecules  are  consonant  one 
with  another. 

Each  cerebral  lobe,  taken  alone,  presents  for  considera- 
tion in  its  turn  : — 

1.  Masses  of  grey  matter. 

2.  Agglomerations  of  white  fibres. 

The  masses  of  grey  matter,  which  are  composed  of 
many  myriads  of  cells,  and  are  the  essentially  active 
regions  of  the  system,  are  arranged  at  the  periphery  in 
the  form  of  a  thin,  undulating,  continuous  layer,  which 
constitutes  the  cerebral  cortex ;  and  in  the  central 
regions  in  the  form  of  two  grey  ganglions,  coupled 
together,  which  are  simply  the  grey  substance  of  the 
optic  thalami  and  corpora  striata  (opto-striate  ganglions). 

The  white  substance,  essentially  composed  of  nerve- 
tubules  in  juxtaposition,  occupies  the  spaces  comprised 
between  the  cortical  periphery  and  the  central  ganglions. 

The  fibres  of  which  it  consists,  and  which  merely 
represent  lines  of  union  between  such  and  such  resfions 
of  the  cortical  periphery  and  such  and  such  regions  of 
the  central  ganglions,  run,  like  a  series  of  electric  wires 
stretched  between  two  stations,  in  two  principal  direc- 
tions. 


lO  THE  BRAIN   AND   ITS   FUNCTIONS. 

1.  Some  directly  unite  the  different  points  of  the 
cortical  periphery  with  the  central  ganglions,  and  are 
lost  in  their  mass. 

These  are  like  the  spokes  of  a  wheel  which  unite  its 
circumference  to  the  central  nave,  which  serves  as  their 
point  of  support.  We  may  therefore  describe  them 
under  the  name  of  converging  fibres. 

2.  The  others,  on  the  contrary,  have  a  transverse  direc- 
r\      tion.     They  proceed  from  one  hemisphere  to  the  other, 

thus  uniting  the  homologous  regions  of  the  brain,  right 
1       and  left. 

It  may  therefore  be  said  that  they  serve  as  an  anas- 
tamosis  and  commissure  between  these  homologous 
regions,  and  that  they  are  thus  the  agents  which  pro- 
duce unity  of  action  between  the  two  cerebral  hemi- 
spheres. This  order  of  fibres,  by  reason  of  its  origin 
and  connections,  may  legitimately  be  designated  by  the 
name  of  commissural  fibres. 

These  data  bsing  admitted,  it  may  be  said  that  the 
anatomic  formula  bj  means  of  which  we  may  define  the 
structure  of  the  cerebrum,  of  man  as  of  the  other  verte- 
brates, is  this :  "  The  cerebrum  is  the  sum  total  of  the 
cerebral  convolutions,  united  one  with  another,  with 
those  on  the  same  side  and  with  those  on  the  other,  and 
simultaneously  with  the  central  opto-striate  ganglions." 

We  shall  now  pass  in  review  the  different  agglome- 
rations of  the  grey  matter,  and  at  the  same  time  give 
a  sketch  of  the  principal  details  of  the  organization  of 
the  white  matter. 


\»> 


^oV^ '^  ^^ 

'^  LIBRARY 


CHAPTER  IT. 

CORTEX  OF  THE  BRAIN — THE  GREY  CORTICAL 
SUBSTANCE. 

Every  one  knows  the  external  appearance  of  the  cortical 
substance  of  the  brain.  It  is  sufficient  to  recall  that  of 
the  brains  of  sheep,  as  served  at  table,  to  see  at  a  glance 
that  the  grey  cortical  substance  presents  the  appearance 
of  a  grey  undulating  layer,  folded  a  great  number  of 
times  upon  itself,  and  thus  forming  a  series  of  multiple 
sinuosities  of  which  the  sole  object  is  the  obtaining  of 
increased  surface. 

These  foldings  and  refoldings,  which  attain  their 
maximum  of  development  in  the  human  species,  appa- 
rently obey  some  fixed  laws  as  regards  their  distribution.* 
Some,  in  fact,  have  permanent  characters  which  render 
them  easily  discoverable  in  all  human  brains  ;  others, 
and  these  form  the  greater  number,  present  all  possible 
varieties  of  external  configuration,  not  only  in  different 
individuals,  but  even  in  the  same  individual,  according 
as  we  inspect  homologous  regions  in  the  right  or  ieic 
hemisphere. 

Take,  for  instance,   a  sheet  of  tracing  paper,  apply 

*  See  the  interesting  description  of  the  topography  of  the  cerebral  convolu- 
fions  given  by  Prof.  Charcot  in  his  lectures  to  the  Faculty. — Progris  Medical, 
X875,  p.  283,  353,  &c. 


12  THE  BRAIN   AND   ITS   FUNCTIONS. 

it  to  a  fresh  vertical  section  of  the  brain,  mark  with 
a  brushful  of  water-colour  the  contour  of  the  cortical 
substance  of  one  hemisphere,  and  fold  the  paper  over  ; 
you  will  thus  see  very  clearly  that  the  outline  of 
the  convolutions  of  one  side  does  not  adapt  itself 
to  those  of  the  other.  I  have  made  such  tracings 
repeatedly,  and  have  never  yet  found  a  human  brain 
completely  symmetrical,  completely  balanced  in  its 
peripheral  regions,  and  with  the  left  regions  of  the 
cortical  substance  exactly  corresponding  to  the  homo- 
logous regions  of  the  opposite  side. 

There  is  another  peculiarity,  which  it  is  important  to 
notice,  in  the  external  examination  of  the  cortical 
substance. 

In  the  adult,  in  vertical  or  horizontal  sections  of  the 
brain,  it  is  evident  that  the  line  of  the  summits  of  the 
convolutions  is  continuous,  that  their  culminating  points 
are  all  on  the  same  level ;  there  is  some  uniformity  in 
the  distribution  of  the  activity  of  nutrition  over  the 
whole  mass. 

As  old  age  advances  different  appearances  begin  to 
show  themselves,  and  in  studying  the  different  effects  of 
senescence  in  all  the  organs,  it  is  curious  to  observe  its 
characteristics  in  the  human  brain. 

We  observe,  then,  that  the  grey  substance  becomes 
diminished  in  thickness  ;  that  its  colour  changes  to 
yellowish  white  in  consequence  of  the  passing  of  the 
nerve-cells  into  the  granulo-fatty  state;  and  that  besides, 
the  convolutions  settle  down  in  isolated  groups,  like 
mountains,  undermined  at  their  bases,  which  insensibly 
subside.  Thus,  in  many  old  men  in  their  dotage,  we 
may  note  that  the  line  joining  the  summits  of  certain 


CORTEX   OF  THE  BRAIN.  13 

groups  of  convolutions  becomes  interrupted  ;  that  a  cer- 
tain number  of  them  are  retracted  and  have  sunk  below 
the  level  of  the  surrounding  convolutions ;  and  that 
thus,  from  the  effect  of  time,  there  exists  a  slow  and 
progressive  absorption  of  the  nervous  substance. 

In  individuals  who  fall  prematurely  into  dotage 
from  alterations  of  the  cerebral  substance,  under  the 
action  of  mental  diseases,  we  find  the  same  atrophy  of 
the  cortical  layer.  Thus  I  have  very  frequently  ob- 
served atrophy  of  the  convolutions  in  young  subjects 
attacked  by  paralytic  dementia,  persons  affected  by 
hallucinations,  and  patients  who  have  suffered  from 
melancholic  delirium. 

The  thickness  of  the  cortical  substance  in  the  adult 
IS  on  the  average  about  two  to  three  millimetres. 
Generally  it  is  more  abundant  in  the  anterior  than  the 
posterior  regions.  Its  mass  varies  according  to  age,  and 
especially  according  to  race,  Gratiolet  remarking  that 
in  races  of  low  stature  the  mass  of  the  cortical  substance 
is  but  small.* 

Its  colour  presents  some  varieties.  It  is  uniformly 
greyish,  and  as  it  were  gelatinous,  in  the  new-born 
infant ;  in  the  child  during  its  first  years  it  is  of  a 
rosy  grey  ;  in  the  old  man  it  acquires  somewhat  of  a 
yellowish-white  colour,  its  vascularity  being  less  distinct 
than  in  the  adult.  In  the  negro  this  substance  is  of  a 
darker  colour  than  in  the  white  man. 

In  the  adult  in  whom  development  is  regularly 
accomplished,  the  cortical  substance  presents  itself  very 
clearly  to  the  naked  eye,  m  the  form  of  stratified  zones, 
differing  slightly  in  colour.     We  observe,  in  fact,  that 

*  "Gratiolet,  Bulletin  de  la  Societe  d  Anthropologie,"  1859,  p.  ^% 


14  THE  BRAIN   AND   ITS   FUNCTIONS. 

there  exists  a  superficial  sub-meningeal  zone  of  a  greyish 
colour,  and  transparent ;  and  a  deeper  zone,  underlying 
the  preceding,  of  a  more  distinctly  reddish  colour. 

When  we  take  a  thin  section  of  this  cortical  sub- 
stance, compress  it  between  two  pieces  of  glass,  and 
examine  it  by  holding  it  up  to  the  light,  as  Bail- 
larger  first  pointed  out,*  we  see  that  it  divides  into 
secondary  zones  of  unequal  transparency,  and  that 
these  zones  cleave  with  a  regular  and  fixed  striation. 
We  shall  see  that  these  appearances  are  merely  the 
result  of  the  minute  structure  of  the  cortical  substance. 

Such  are  the  characters  which  the  cerebral  cortex 
presents  to  the  naked  eye,  and  which  every  one  may 
observe  in  fresh  brains. 

Let  us  now  penetrate,  by  means  of  magnifying 
glasses,  into  the  interior  of  this  soft  substance,  amorph- 
ous in  appearance,  of  which  the  homogeneous  aspect  is 
far  from  revealing  to  us  its  marvellous  details. 

Let  us  push  our  researches  still  further  by  means 
of  thin  sections  rendered  transparent  and  methodically 
coloured  ;  let  us  employ  gradually  increasing  powers 
to  pass  from  a  known  to  an  unknown  region  ;  and 
avail  ourselves  of  the  magnifying  processes  that  photo- 
graphy places  at  our  disposal.  We  shall  then  be  able  to 
penetrate  into  these  almost  unknown  regions  of  the 
world  of  the  infinitely  little,  and,  like  travellers  re- 
turned from  distant  lands,  to  bring  back  various  pho- 
tographic images — indisputably  faithful  reproductions 
of  the  details  which  have  struck  us  in  the  course  of  our 
voyage  of  discovery. 

We    now    find    in    the    cortical   substance    a    fixed 

♦  "  Memoires  de  I'Academie  de  Medecine  de  Paris,"  1840. 


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l6  THE   BRAIN   AND   ITS   FUNCTIONS. 

anatomical  element — an  ultimate  morphological  unit. 
This  is  the  nerve-cell,  with  its  various  attributes  and 
definite  configuration,  its  nerve-fibres,  connective-tissue, 
and  capillaries  ;  and  we  must  now  examine  the  consti- 
tution of  this  cortical  nerve-cell,  its  forms,  its  connections, 
and  its  relations. 

Imagine  a  number  of  small  pyramidal  bodies,  disposed 
in  series,  parallel  to  one  another,  united  to  one  another 
by  means  of  an  intermediary  network,  and  moreover 
regularly  stratified,  and  thus  forming  layers  successively 
piled  up,  like  the  strata  of  the  terrestrial  cortex.  Such 
is  the  general  aspect  that  a  thin  complete  section  of  the 
cortical  substance  presents. 

If  we  add  that  the  cerebral  nerve-fibres  enter,  into 
intimate  connection  with  this  network  of  cells,  and  are 
insensibly  lost  in  the  surrounding  tissue,  we  shall  then 
have  a  complete  expression  of  the  organization  of  the 
cerebral  cortex. 

Now  if  we  observe  each  of  the  nerve-cells  singly, 
we  discover  that  they  all  have  a  pyramiidal  form  ;  that 
they  are  of  unequal  volume  ;  that  the  smaller  occupy 
the  superficial  or  sub-meningeal,  the  larger  the  deeper 
ref^ions  ;  that  these  latter  are  on  an  average  double  the 
size  of  their  fellows,  and  that  the  transition  from  small 
to  large  cells  is  accomplished  by  insensible  gradations, 
the  cells  of  the  intermediate  zones  in  general  presenting 
mixed  characteristics. 

The  cells  have  in  addition  one  extremely  remarkable 
peculiarity,  which  gives  to  the  histological  preparations  of 
this  region  a  special  physiognomy,  viz.,  their  character- 
istic arrangement.  It  is  indeed  very  curious  to  observe 
that,   wliile  they  are  all,   as  we  have  seen,   pyramidal 


THE   GREY  CORTICAL  SUBSTANCE.  I7 

in  form,  the  summit  of  each  is,  so  to  speak,  attracted 
towards  the  superficial  regions,  Hke  a  series  of  needles 
magnetized  so  as  to  point  towards  the  pole;  so  that  their 
bases  are  all  parallel  and  are  directed  towards  the  point 
from  which  the  nerve-fibres  arrive. 

They  give  off  from  their  substance  a  species  of  very 
delicate,  rootlet-like,  hirsute  fringe,  which  gradually 
spreads  out  and  forms  on  all  sides  a  surrounding 
network  ;  and  as  each  cell  presents  a  similar  arrange- 
ment, the  result  is  that  a  close  union  between  them  is 
produced,  so  that  they  form  throughout  the  cerebral 
cortex  a  continuous  true  plexus,  all  the  molecules  of 
which  are  by  some  means  arranged  so  as  to  vibrate  in 
unison. 

By  their  prolongations,  which  form  the  base  of  the 
pyramid,  they  enter  more  or  less  directly  into  relation 
with  the  afferent  nerve-fibres  ;  while  their  apices  send 
out  a  filamentous  prolongation,  which  proceeds  either 
to  be  lost  in  the  surrounding  network,  or  to  enter 
into  contact  with  certain  zones  of  cells  situated 
above. 

The  number  of  cells  in  the  cortical  substance  must 
be  estimated  at  mkny  thousands.  The  following  data 
are  suf^cient  to  make  this  clear. 

In  a  space  of  cortical  substance  equal  to  i  square 
millimetre,  and  of  a  thickness  of  ^Vth  of  a  millimetre,  lOO 
to  120  nerve-cells  of  various  sizes  have,  on  an  average, 
been  counted.  If  now  we  form  in  imagination  an  esti- 
mate of  the  ratio  of  this  small  portion  of  the  cortical 
substance  to  the  whole,  we  shall  arrive  at  an  estimate 
of  many  thousands. 

The  colour  of  the  cortical  cells  in  fresh  healthy  brains 


iS  THE   BRAIN   AND   ITS   FUNCTIONS. 

is  an  amber  yellow.  They  are  apparently  provided  with 
a  bright  nucleus  and  with  a  nucleolus.* 

The  internal  structure  of  the  cerebral  cell  individually 
considered,  seems  to  grow  more  complex  the  deeper  we 
proceed  in  the  minute  study  of  its  elements. 

Some  years  ago  anatomists  admitted  of  an  investing 
membrane,  and  a  contained  substance,with  a  nucleus  and 
a  nucleolus,  in  the  constitution  of  the  cell  ;  later  they 
discovered  that  its  investing  membrane  was  nothing 
more  than  the  external  layer  of  an  amorphous  proto- 
plasm, surrounding  the  nucleus  of  the -cell,  and  prolonging 
itself  externally  in  the  form  of  multiple  ramifications. 

At  the  present  day  things  seem  to  complicate  them- 
selves still  further ;  for  I  have  lately  discovered  in^some 
researches  as  yet  unpublished,  that  this  substance  which 
we  call  the  protoplasm  of  the  cell  is  formed  by  a  true 
tissue  organized  in  a  special  manner  ;  that  this  tissue, 
consisting    of    very    delicate    fibrillae     interlaced    like 

*  The  cells  of  the  cortical  substance  were  perrectly  described  by  Malpighi 
in  the  year  1687,  and,  strange  to  say,  left  in  oblivion  by  the  majority  of  anato- 
mists during  the  interval  between  him  and  us.  It  is  only  in  our  time  that  they 
liave  been  more  definitely  brought  to  light.  "  I  have  thus  discovered,"  says 
Malpighi,  "by  the  dissections  I  have  made  of  the  brains  of  sound  animals, 
that  the  cortical  substance  of  the  brain  consists  of  numbers  of  small  glands 
piled  up  and  united  together.  These  glands,  in  which  are  inserted,  or  rather 
from  which  spring  the  white  roots  of  the  nerves,  are  so  intricately  arranged, 
joined,  and  connected  with  one  another  in  these  regions  of  the  brain,  which 
resemble  little  tangled  thickets,  that  they  form  by  their  assemblage  the  cortex 
or  external  superficies  of  the  brain.  They  are  of  an  oval  shape,  which  is, 
however,  always  more  or  less  flattened,  from  their  pressing  one  upoi  another 
on  all  sides.  From  their  internal  parts  there  springs  a  white  nerve  fibre,  which 
is  as  it  were  the  vessel  belonging  to  them,  and  which  may  be  clearly  seen 
through  these  small  transparent  and  entirely  white  bodies:  so  that  the  white 
substance  of  the  brain  is  apparently  a  tissue  and  an  assemblnge  of  several  sorts 
of  small  fibres  joined  together,  etc.  etc"  ("  De  la  stiuciure  des  visccres,"  Paris* 
1687.) 


THE   GRLY    CORTICAL   SUBSTANCE. 


19 


the  wicker-work  of  an  osier-basket,  has  a  tendency  to 
agglomerate  towards  the  nucleus  of  the  cell,  which  thus 


Fig.  2. — Cortical  cell  of  the  deeper  zones  at  about  boo  diameters;  a  section  of 
the  cell  is  made  through  its  greater  axis,  its  interior  texture  being  thus  laid  bare. 
A  represents  the  superior  prolongation  radiating  from  the  mass  of  the  nucleus  itself; 
B,  lateral  and  posterior  prolongations ;  c,  spongy  areolar  substance,  into  which  the 
structure  of  the  cell  itself  is  resolved  ;  d,  the  nucleus  itself  seems  only  to  be  a  thickening 
of  this  areolar  stroma — it  sometimes  has  a  radiated  arrangement ;  e,  tne  bright  nucleolus 
is  itself  decomposable  into  secondary  filaments. 

becomes  a  true  point  of  concentration  ;  that  the  nucleus 


20  THE   BRAIN   AND   ITS   FUNCTIONS. 

itself  is  not  homogeneous  ;  that  it  is  endowed  with  a 
special  structure,  radiated  in  appearance;  and  that  lastly 
the  nucleolus,  considered  as  the  final  expression  of  the 
unity  of  the  nerve-cell,  is  in  its  turn  divisible  into 
secondary  filaments. 

Imagination  is  corifounded  when  we  penetrate  into 
this  world  of  the  infinitely  little,  where  we  find  the 
same  infinite  divisions  of  matter  that  so  vividly  impress 
us  in  the  study  of  the  sidereal  world  ;  and  when  we 
thus  behold  the  mysterious  details  of  the  organization 
of  an  anatomical  element,  which  only  reveal  them- 
selves when  magnified  from  700  to  800  diameters, 
and  think  that  this  same  anatomical  element  repeats 
itself  a  thousandfold  throughout  the  whole  thickness  of 
the  cerebral  cortex,  we  cannot  help  being  seized  with 
admiration  ;  especially  when  we  think  that  each  of 
these  little  organs  has  its  autonomy,  its  individuality, 
its  minute  organic  sensibility  ;  that  it  is  united  with  its 
fellows;  that  it  participates  in  the  common  life;  and 
that  above  all  it  is  a  silent  and  indefatigable  worker, 
discreetly  elaborating  those  nervous  forces  of  the 
psychic  activity,  which  are  incessantly  expended  in  all 
directions  and  in  the  most  varied  manners,  according  to 
the  difi"erent  calls  which  are  made  upon  it,  and  set  it 
vibrating. 

The  nerve-fibres  which  represent  the  bonds  of  union 
between  the  cortical  substance  and  the  central  regions 
of  the  brain  emerge  from  the  midst  of  the  plexus 
of  cells.  They  all  at  first  appear  as  isolated  filaments, 
as  a  derivation,  mediate  or  immediate,  from  the 
tissue  proper  to  each  cell ;  then  by  degrees,  as  they 
proceed  between  the  ranges  of  cells,  they  enlarge,  their 


THE   GREY   CORTICx\L   SUBSTANCE.  21 

sheath  thickens,  the  interposed  fatty  substance  becomes 
more  abundant,  and  they  are  insensibly  transformed 
from  grey  to  white  fibrils.  As  to  their  mode  of  central 
arrangement  they  behave  in  a  manner  which  we  shall 
explain  further  on. 

Neuroglia. — Among  the  elements  which  enter  into 
the  structure  of  the  cerebral  cortex,  the  uniting  sub- 
stance, the  neuroglia  as  it  is  called,  plays  a  primary  part 
as  regards  its  anatomical  connections  and  physiological 
properties. 

Imagine  a  web  of  extreme  delicacy,  radiating  from 
the  walls  of  the  sheaths  of  the  capillaries  of  the  cerebral 
membranes,  and  immediately  enveloping  the  cortical  sub- 
stance; its  prolongations,  like  an  infinite  number  of  root- 
lets, everywhere  plunging  into  this  substance.  Imagine 
this  delicate  web,  having  resolved  itself  into  a  network 
of  greater  and  greater  attenuation,  forming  meshes  more 
and  more  closely  woven,  in  the  midst  of  which  the  nerve- 
cells  are,  to  borrow  the  picturesque  simile  of  Malpighi, 
embedded  like  pomegranate  seeds,  in  the  midst  of 
the  white  fibrous  tissue  which  encloses  them  on  all 
sides. 

These  same  neuroglian  filaments  thus  envelop  the 
nerve-cells  with  their  inextricable  web,  just  as  the 
cellular  tissue,  for  instance,  surrounds  the  lymphatic 
ganglions;  and  thus  is  constituted  that  immense  network 
of  connective-tissue  everywhere  continuous  through- 
out the  nervous  system,  from  the  spinal- cord  to  the 
brain,  serving  to  support  all  the  individual  anatomic 
elements,  and  by  its  softness,  delicacy,  and  extreme 
divisibility,  forming  for  them  a  veritable  cement  which 
solders  them  together,  uniting  them  in  a  perfect  unity, 


22  THE   BRAIN   AND   ITS   FUNCTIONS. 

while  at  the  same  time  it  serves  them  as  a  means  of 
nutrition. 

This  network  of  the  neurogUa  presents,  moreover,  a 
very  remarkable  arrangement  in  the  cortical  substance. 
Not  only  does  it  incorporate  itself  with  each  particular 
cellular  element,  and  with  the  nerve-fibres,  serving  them 
in  a  manner  as  a  mechanical  protection,  but  besides 
this  it  plays  an  analogous  part  as  regards  the  nervous 
elements  of  the  cortex  as  a  whole. 

Thus,  if  we  examine  the  superficial  layers  of  each 
convolution  in  the  sub-meningeal  regions,  we  perceive 
that  the  neuroglia  forms,  immediately  above  the  last 
zones  of  nerve- cells,  a  thin  areolar  layer  of  an  appre- 
ciable thickness,  constituting  a  sort  of  spongy  cushion 
everywhere  continuous.  It  is,  in  fact,  a  means  of 
protection  and  isolation  which,  as  it  were,  filters  the 
nutrient  juices  flowing  from  the  meninges,  and  prevents 
the  plexus  of  nerve-cells,  thus  protected  by  this  variety 
of  natural  epithelium,  from  coming  nakedly  into  direct 
contact  with  the  capillaries  of  the  meningeal  mem- 
branes.    (See  Fig.  I,  A.) 

The  capillaries  similarly  play  a  very  important  part 
in  the  structure  of  the  cortical  layer.  They  represent 
the  most  important  of  the  nutritive  elements  that  bring 
to  the  nerve-cell  the  pabulum  vitce  necessary  for  the 
maintenance  of  its  daily  activity. 

Radiating  in  the  form  of  little  canals  from  the  deep 
surface  of  the  meninges,  they  plunge  like  very  delicate 
rootlets  into  the  midst  of  the  nervous  elements^  dividing 
themselves  into  a  network  of  greater  and  greater  tenuity, 
and  their  meshes,  becoming  closer,  pass  around  the 
circumference  of   each  group  of  cells  to  form  areolae 


THE   GREY   CORTICAL   SUBSTANCE.  23 

extremely  rich  in  blood-vessels.  It  is  a  very  remarkable 
fact  that  these  same  capillaries,  which  directly  penetrate 
the  texture  of  other  organs  and  come  in  contact  with 
the  active  elements  which  it  is  their  task  to  nourish 
have  a  special  arrangement  as  regards  the  nervous  ele- 
ments. A  peculiar  adventitious  sheath,  in  fact,  surrounds 
their  walls,  like  a  muff,  for  a  part  of  their  circumference, 
isolating  them  from  the  nervous  elements  themselves; 
so  that  it  is  but  mediately  that  these  obtain  their  share 
in  the  processes  of  nutritive  life. 

To  sum  up,  the  structure  of  the  cerebral  cortex  may 
be  reduced  to  the  following  propositions  : — 

The  cortical  substance  is  composed  of  fixed  ana- 
tomical elements,  distributed  in  an  infinite  number 
throughout  its  mass — the  cerebral  nerve-cells. 

These  lie  in  juxtaposition  and  enter  into  close  relation- 
ship one  with  another.  They  are  further  arranged  in 
regularly  stratified  zones  one  above  another ;  and  they 
form  by  their  prolongations  a  tissue  which  is  everywhere 
continuous,  and  thus  produces  unity  of  action  between 
this  multitude  of  isolated  elements. 

As  physiological  deductions,  the  following  conse- 
quences spring  from  the  considerations  previously  stated. 

The  cortical  substance  represents  an  immense  instru- 
ment constituted  of  nervous  elements,  each  gifted,  it  is 
true,  with  its  proper  individuality,  and  yet  intimately 
connected  one  with  another. 

The  series  of  cells  arranged  in  stratified  zones,  and 
the  connections  of  the  different  strata  communicating 
one  with  another,  imply  the  idea  that  the  nervous 
activities  of  each  zone  may  be  isolatedly  evoked ; 
that  they   may  be  associated  one  with  another  ;   that 


24  THE   BRAIN    AND   ITS   FUNCTIONS. 

they  may  be  modified  in  passing  from  one  region  to 
another,  according  to  the  nature  of  the  intermediary^ 
cells  brought  into  play  ;  that,  in  a  word,  nervous  actions, 
like  vibratory  undulations,  must  propagate  themselves 
through  one  point  of  contact  after  another,  following 
tlie  direction  of  the  organic  substance  that  underlies 
them,  either  transversely  or  vertically,  from  the  super- 
ficial to  the  deep  regions,  and  vice  versa. 

On  the  other  hand,  as  regards  the  physiological  signi- 
ficance of  certain  zones,  and  the  relation  of  each  to 
the  phenomena  o(  sensation  and  motion,  we  may,  by 
the  laws  of  analog\%  suppose  that  the  sub-meningeal 
reg'ons,  principally  occupied  by  the  small  cells,  may  be 
specially  connected  with  the  phenomena  of  sen^&tion, 
while  the  deeper  regions  occupied  by  groups  of  large 
cells  may  be  considered  as  the  most  important  regions 
tliat  give  rise  to  motor  phenomena. 

In  fact,  in  applying  to  this  question  the  data  which 
are  acquired  from  the  study  of  the  spinal  cord,  and  which 
show  us,  for  example,  that  where  there  are  small  cells 
(posterior  horns)  the  phenomena  connected  with  sensi- 
bility take  place,  and  where,  on  the  contrary,  there  are 
large  cells  (anterior  horns),  motor  impulses  are  deve- 
loped— it  is  rational,  I  assert,  to  see  physiological 
where  there  are  morphological  analogies,  and  to 
consider  the  sub-meningeal  regions  of  the  small  cells 
of  the  cortical  substance  as  being  the  natural  sphere 
of  the  diffusion  of  general  and  special  sensation,  and 
therefore  the  great  common  reser\'oir  of  all  the  united 
sensibilities  of  the  organism.  And  on  the  other  hand, 
we  may  consider  the  deep  zones  as  being  tlie  centres 
for  preparing  and  emitting  motor  stimulL 


THE  GREV  CORTICAL  SUBSTANCE.  2$ 

This  mode  of  considering  the  cerebral  cortex,  in  its 
totality,  as  an  instrument  essentially  sensori-motor, 
conceived  on  the  same  plan  as  that  of  the  sensori-motor 
instruments  of  the  spinal  cord,  will  permit  of  the  formu- 
lation of  certain  new  propositions  on  the  subject  of  the 
evolution  and  intra-cerebral  transforDiation  of  the  pheno- 
mena of  sensibility  into  motor  reaction. 


CHAPTER  III. 

THE  WHITE   SUBSTANCE   OF   THE   BRAIN. 

The  white  substance  of  the  brain  is  composed  of  a  series 
of  tubules  in  exact  juxtaposition,  and  serving  as  it  were 
as  isolated  conductors  for  each  group  of  cells  with 
which  they  are  in  connection,  like  the  electric  wire  that 
carries  the  imponderable  matter  secreted  by  the  pile  with 
which  it  is  united. 

These  nervous  tubules,  of  which  the  general  direc- 
tion is  perceptibly  rectilinear,  are,  like  the  nerve-cells 
so  closely  related  to  them,  distributed  in  very  consider- 
able numbers,  seeing  that  they  constitute  the  mass  of 
the  white  cerebral  substance  of  the  two  hemispheres. 

They  are  essentially  composed  of  a  fundamental  fibre 
designated  as  the  axis  cylinder,  which  represents  the  true 
nervous  element  of  the  tubule ;  and  it  is  this  fibril  that 
usually  enters  into  direct  connection  with  the  essential 
structure  of  the  nerve-cell. 

This  fundamental  fibril  is  surrounded,  as  with  a  muff, 
by  a  sheath  of  connective  tissue,  of  variable  thickness 
according  as  it  is  observed  in  the  central  or  peripheral 
regions  of  the  system.  Between  this  sheath  and  the  axis 
cylinder  there  is  placed  a  fatty,  oleo-phosphoric,  highly 
refracting  substance,  the  myeline,  which  forms,  as  it  were, 
a  fluid  isolating   body    between    these    two   elements. 


THE   WHITE   SUBSTANCE  OF   THE   BRAIN. 


27 


The  neuroglia,  with  its  thousands  of  meshes  infinitely 
divided,  similarly  forms  around  the  nerve-tubules  a 
closely-woven  network,  which   sustains  them   and  con- 


FiG.  3.  —  Diagram  of  the  commissural  fibres  of  the  anterior  regions  of  the  brain. 
These  form  a  series  of  curves  one  within  another,  the  extremities  of  each  of  which 
phmge  into  the  homologous  regions  of  each  cerebral  lobe,  i,  i',  2,  2', — 3  and  3'.  They  pass 
through  the  middle  line,  and  at  4  and  4'  give  rise  to  the  various  appearances  which  the 
corpus  callosum  presents.  5.  Commissural  fibres  of  the  inferior  regions.  These  are 
curved  in  an  inverse  direction  is  regards  the  former,  the  convexity  of  each  set  being 
presented  towards  that  of  the  other. 

stitutes  a  uniting  frame-work,  and  a  veritable  cement  in 
the  midst  of  which  they  are  imbedded. 

These  thousands  of  nervous  elements,  thus  constituted, 
emerge  isolatedly  from  the  different  zones  of  the  cortex, 
either  directly,  from  the  essential  protoplasmic  structure 
of  the  nerve-cells,  or  indirectly,  by  springing  from  the 
midst  of  the  intercellular  tissue,  in  the  form  of  grey 
transparent  fibrils,  covered  with  an  exceedingly 
delicate   sheath.     By   degrees,   in    consequence   of  the 


28  THE  BRAIN   AND   ITS   FUNCTIONS. 

interposition  of  the  myeline,  which  becomes  more  abun- 
dant between  the  cylinder  and  the  sheath,  these  grey  fibrils 
assume  the  condition  of  white  fibres,  and,  having  at- 
tained the  constitution  of  complete  nervous  elements, 
pursue  their  way  in  a  given  direction,  to  be  decomposed, 
in  the  last  stage  of  their  course,  in  the  satellite  masses  of 
grey  matter  with  which  they  are  particularly  connected. 

The  white  nerve  fibres,  like  true  bonds  of  union,  serve 
then  merely  to  connect  two  regions  of  associated  cells, 
and  thus  to  establish  between  them  a  natural  channel 
for  the  propagation  of  nervous  activity.  From  this 
standpoint  they  are  quite  comparable  to  the  nerve-fibres 
interposed  between  each  of  the  ganglions  of  the  sympa- 
thetic, and  serving  as  a  bond  of  connection  between  them. 

This  being  understood,  let  us  see  how  these  fibrillary 
elements  behave,  what  particular  direction  they  follow, 
and  what  relations  they  establish  with  the  different 
central  regions. 

Generally  speaking  the  white  cerebral  fibres  take  two 
directions. 

I.  The  first  group  of  the  commissural  fibres  runs  in 
a  perceptibly  tranverse  direction. 

Originating  in  the  midst  of  the  plexus  of  cells  qf 
the  cortical  substance,  after  having  travelled  with  their 
partners  for  a  while  they  separate  from  them  one  by  one, 
abandon  their  primitive  direction,  pass  across  the  mesial 
line,  and  are  finally  lost  in  the  homologous  regions  of 
the  opposite  hemisphere.     (Figs.  3  and  4.) 

They  thus  constitute  the  transverse  fibres  of  the  vault 
of  the  corpus  callosum,  to  which  those  of  the  anterior 
white  commissure  are  attached. 

They    individually    present     themselves     as     curvi- 


THE    WHITE   SUBSTANCE   OF   THE   BRAIN. 


29 


linear  fibres  in  the  form  of  an  U  ;  and  the  branches  of 
this  U  pkmge  in  a  similar  manner  into  the  homologous 
legions  of  both  hemispheres. 

This  collection  of  transverse  white  fibres,  which, 
taken  as  a  whole,  forms  a  little  more  than  half  the 
white    mass    of   the    cerebral    hemispheres,  establishes, 


Fig.  4.— Diagram  of  the  commissural  fibres  on  the  level  of  the  corpus  striatum— i.  i'. 
Groups  of  transverse  fibres,  one  within  another,  continuous  with  those  in  the  previous 
figure— 2,  2'.  Grey  substance  of  corpus  striatum— 3'.  Groups  of  inferior  commissural 
fibres— 4,  4'.  These  curve  into  the  shape  of  an  S  to  accommodate  the  corpus  striatum, 
which  they  help  to  limit  externally 

therefore,  intimate  connections  between  homologous 
regions  of  the  cortical  substance.  The  fibres  them- 
selves are  thus,  by  reason  of  their  relations  with  the 
grey  elements,  true  commissures  distributed  every- 
where   in    infinite    numbers.      We    may   also    say   that 


30  THE   BRAIN   AND   ITS   FUNCTIONS. 

they  constitute  a  very  distinctly  defined  system  of 
fibres,  which  by  reason  of  its  anatomical  function  may 
be  in  a  general  manner  denominated  a  system  of  com- 
missural fibt'es. 

From  a  physiological  point  of  view,  on  the  direction 
of  this  order  of  fibres  we  might  base  the  induction  that  it 
is  by  means  of  them  that  the  regions  of  the  two  cerebral 
hemispheres  are  regularly  anastomosed,  cell  to  cell ;  and 
that  they  are,  from  this  very  fact,  the  true  agents  in  the 
unity  of  action  of  the  two  cerebral  lobes. 

2.  The  second  group  of  white  fibres  (converging 
fibres),  no  less  important  than  the  preceding,  follows  a 
rectilinear  and  sensibly  converging  direction.  This 
system  of  fibres  is  entirely  developed  within  the.  same 
hemisphere  from  which  it  is  derived.  It  has  nothing 
in  common  with  the  opposite  hemisphere. 

The  fibres  of  which  it  consists  originate  with  their 
fellows,  the  commissural  fibres,  at  all  points  of  the 
cortical  periphery,  in  the  midst  of  the  plexus  of  cells, 
in  the  form  of  grey  fibrils,  and  proceed  along  the 
common  track  for  a  certain  time.  Arrived  at  the  level 
of  the  wall  of  the  superior  angle  of  the  ventricles,  the 
commissural  fibres  pass  to  the  opposite  side,  while  these 
insensibly  approach  one  another  like  a  series  of  rays^ 
radiating  from  the  periphery  of  a  hollow  sphere,  group 
themselves  in  the  form  of  great  white  cylindroid  fascicles 
placed  in  juxtaposition,  and  are  inserted,  like  pins  in  a 
pincushion,  around  the  anterior,  middle,  and  posterior 
regions  of  the  optic  thalamus  of  the  corresponding 
hemisphere. 

By  reason  of  the  direction  and  special  mode  of  group- 
ing of  the  nervous  elements  which  thus  serve  as  a  bond 


THE   WHITE   SUBSTANCE   OF   THE   BRAIN. 


31 


of  union  between  the  peripheral  and  central  regions  of 
the  brain,  we  cannot  but  recognise  that,  anatomically, 
they  play  the  part   of  converging  elements  and   con- 


Fig.  5. — Diagram  of  the  converging  fibres  and  their  relations  to  the  central  grey 
ganglions — i.  Converging  fibres  of  the  posterior  convolutions  of  the  brain — 2.  Converg- 
ing fibres  of  the  middle  convolutions  of  the  brain — 3.  Converging  fibres  of  the  anterior 
convolutions  of  the  brain — 4,  4',  4".  Cortical  periphery  as  related  to  the  central  grey 
ganglions — 5.  Optic  thalamus— 6.  Corpus  striatum — 7.  Anterior  (olfactor^O  centre — 
8.  Middle  (optic)  centre — 9.  Median  (sensitive)  centre — 10.  Posterior  (acoustic)  centre — 
II.  Central  grey  region — 12.  Ascending  grey  fibres  of  visceral  innervation—  13.  Grey 
optic  fibres — 14.  Ascending  sensitive  fibres — 15.  Ascending  acoustic  fibres — 16.  Series 
of  anterolateral  fibres  of  the  axis  going  to  be  lost  in  the  corpus  striatum. 

stitute  a  system,  as  well  defined  as  the  former,  which  we 
have  described  under  the  name  of  converging  fibres. 
As  regards  the  behaviour  of  each  group  of  converging 


32  THE  BRAIN   AND   ITS   FUNCTIONS. 

fibres,  it  is  not  our  business  in  this  work  to  give  a 
detailed  anatomic  description  of  each  of  them.  We 
shall  only  mention  that,  whether  we  consider  them  in 
the  posterior,  middle,  or  anterior  regions  of  the  brain, 
we  find  them  everywhere  disposed  in  a  similar  manner, 
and  directed  towards  their  proper  centre  of  attraction. 

Thus  the  converging  fibres  of  the  posterior  convo- 
lutions follow  a  common  postero-anterior  direction ; 
those  of  the  anterior  the  reverse  ;  while  those  of  the 
superior  convolution  run  from  above  downwards,  and 
those  of  the  inferior  from  below  upwards. 

Such  are  the  special  characters  of  the  two  great  sys- 
tems of  fibres  which  constitute  the  white  substance  of 
the  brain.  These  fibres  run  in  a  fixed  direction,  ^obey 
definite  laws,  and  thus  become  the  fundamental  frame- 
work which  on  the  one  hand  binds  together  the  homo- 
loo-ous  regions  of  the  two  hemispheres,  and  on  the  other 
establishes  the  organic  union  between  the  peripheral 
regions  and  central  ganglions  of  the  brain. 

This  concentration  of  the  converging  fibres  around 
the  optic  thalamus  once  effected,  what  becomes  of  these 
nervous  elements,  and  how  do  they  become  lost  in  its 


mass 


? 


From  the  moment  in  which  they  are  implanted  in 
the  circumference  of  the  optic  thalamus,  they  become 
dispersed  by  degrees,  insensibly  taper  away,  and  we 
then  see  them,  in  the  form  of  whitish  rectilinear  fibrils, 
continue  the  converging  direction  of  the  primitive 
fascicles,  and  finally  lose  themselves  in  the  midst  of  the 
different  agglomerations  of  grey  matter  that  they  meet 
in  their  passage  (centres  of  the  optic  thalamus  and 
corpus  striatum). 


THE  WHITE   SUBSTAJSfCE   OF  THE  BRAIN.  33 

Thus  it  is  that  each  region  of  the  cortical  periphery  is 
united,  by  means  of  these  white  fibres,  to  a  symmetrical 
region  in  this  common  ganghon  of  grey  matter  (the 
optic  thalamus),  and  that  these  two  foci  of  nervous 
activity,  the  cortical  periphery  and  the  central  ganglion, 
like  two  electric  piles  united  by  a  common  wire,  are 
intimately  united  into  a  single  instrument. 


CHAPTER   IV. 

THE   OPTIC   THALAMUS. 

Having  thus  passed  in  review  the  structure  of  the  cor- 
tical substance,  and  the  direction  of  the  white  fibres 
which  emerge  from  it,  it  is  now  necessary  to  begin  the 
study  of  the  optic  thalamus  and  corpus  striatum,  in  the 
substance  of  which  these  white  fibres  are  lost ;  these 
being,  as  it  were,  the  natural  pivots  around  which  all  the 
elements  of  the  system  gravitate. 

The  central  mass  of  grey  matter  which  is  usually 
designated  the  optic  thalamus,  and  of  which  the  anato- 
mical structure  and  general  relations  were  scarcely 
known  until  the  present  day,  is  an  ovoid  body  of  red- 
dish colour,  situated  in  the  very  middle  of  the  brain, 
a  fact  easily  verifiable  with  a  pair  of  compasses.  It  is 
in  a  manner  the  centre  of  attraction  of  all  the  fibres, 
the  grouping  and  direction  of  which  it  thus  governs. 

It  is  composed  :  (i).  Of  a  series  of  small  isolated 
ganglions  of  grey  matter,  situated  one  behind  another  in 
a  line  which  runs  in  an  antero-posterior  direction  ;  (2).  Of 
two  slender  bands  of  greyish  material,  lining  the  inter- 
nal  surface  of  the  third  ventricle,  and  continuous  with 
the  grey  matter  of  the  spinal  cord,  which  thus  ascends 
into  the  interior  of  the  brain. 

I.  The  isolated  ganglions  are  four  in  number.     These 


THE   OPTIC  TIIALAINIUS.  35 

have  already  been  described  by  anatomists,  Arnold  in 
particular,*  with  the  exception  of  the  median  ganglion, 
the  existence  of  which  has  been  revealed  by  my  own 
researches.  They  are  arranged,  as  has  been  said,  in  an 
antero-posterior  direction,  and  form  successive  tuberosi- 
ties on  the  surface  of  the  optic  thalamus,  which  give 
it  the  multilobular  appearance  of  a  conglomerate  gang- 
lion.    (See  7,  8,  9,  10,  Figs.  5  and  6.) 

The  anterior  ganglion  is  the  most  prominent.  It  is 
very  much  developed  in  the  animal  species  in  which  the 
development  of  the  olfactory  nerve  is  very  well-marked 
{corpiLs  album  subroUmdurn  of  anatomists). 

Immediately  behind  comes  a  second,  the  middle 
ganglion,  which  in  man  is  comparatively  the  most 
apparent  and  the  most  fully  developed.  In  those  ani- 
mal species  in  which  the  optic  nerves  are  rudimentary, 
the  mole  in  particular,  this  ganglion  is  on  the  contrary 
scarcely  visible. 

Behind  the  preceding,  and  in  the  very  centre  of  the 
optic  thalamus,  we  meet  with  a  third  ganglion,  of  the 
size  of  a  large  pea,  and  whitish  in  appearance,  which 
from  its  situation  I  propose  to  call  the  'inedian  centre. 

Finally,  behind,  in  the  neighbourhood  of  the  superior 
ttiberctcla  qiiadrigeinina,  we  find  another  ganglion,  of 
which  the  contours  are  in  general  vaguely  defined,  and 
which  constitutes  the  posterior  centre.f 

By  means  of  a  series  of  sections,  either  vertical  or 
horizontal,  we  may  convince  ourselves  that  these  small 
ganglions  form  circumscribed   and   very  distinctly  iso- 

*  See  "Tabula;  Anatomicas." — Arnold,  Icones  cerebri  et  medullas  spinalis.' 
Turici,  1858. 

f  See  "  Iconographie  photographique  des  centres  nerveux."'  Plates,  a,  4,  6, 
7,  8,  26,  28. 


^6  THE   BRAIN   AND   ITS   FUNCTIONS. 

lated  masses  of  grey  matter,  composed  of  plexuses  of 
anastomosing  cells;  and  that  they  in  reality  form  small 
independent  centres  in  regular  juxtaposition,  and  iso- 
latedly  communicating  with  special  groups  of  afferent 
nerve-fibres. 

Now  what  is  their  true  signification  from  a  physio- 
logical point  of  view  ? 

Up  to  the  last  few  years  the  function  of  this  mass  of 
grey  matter  which  forms  the  optic  thalamus  was  an 
insoluble  problem  for  anatomists.  It  was  like  an  un- 
known land,  of  which  anatomy  had  barely  ascertained 
the  situation.  Thus,  a  fortiori^  it  may  be  comprehended 
that  it  was  far  from  possible  to  point  out  the  signifi- 
cance of  each  of  these  isolated  ganglions. 

It  was  by  applying  myself  to  the  study  of  the  con- 
nections of  each  of  these  little  isolated  centres  with  the 
peripheral  nervous  expansions  which  are  distributed 
to  them,  and  by  confronting  these  new  data  with 
the  facts  which  comparative  and  pathological  anatomy 
had  revealed  to  me,  that  I  was  led  to  consider  them  as 
so  many  small  isolated  and  independent  foci  of  con- 
centration for  the  different  kinds  of  sensorial  impressions 
which  are  conveyed  to  their  substance.* 

Thus,  if  we  take  the  anterior  centre,  for  instance, 
(Fig.  6),  we  see  that  it  is  directly  united,  by  means  of  a 
series  of  curvilinear  fibrils,  described  by  anatomists 
under  the  name  of  tcenia  semicircular  is,  with  a  particular 
mass  of  grey  matter  situated  at  the  base  of  the  brain, 
and  itself  directly  receiving  the  external  root  of  the 
olfactory  nerve.     Direct  anatomical  examination  shows, 

*  See  Luys,  "  Recherches  anatomiques,  physiologiques  et  pathologiques  sui 
les  centres  nerveux,"  1865. 


THE   OPTIC  THALAMUS.  37 

then,  that  there  are  intimate  connections  between  the 
anterior  centre  and  the  peripheral  olfactory  apparatus. 
(20,  Fig.  6.) 

On  the  other  hand,  in  confirmation  of  this,  in  the 
animal  species  in  which  the  olfactory  apparatus  is  very 
much  developed,  this  ganglion  itself  is  proportionally 
very  well  marked. 

Analogy  has  thus  led  us  to  conclude  that  this  ganglion 
is  in  direct  connection  with  olfactory  impressions,  and 
that  this  marks  it  as  the  point  of  concentration 
towards  which  they  converge  before  being  radiated 
towards  the  cortical  periphery. 

This  simple  and  purely  anatomic  view  was,  for  myself, 
to  some  extent  a  ray  of  light,  and  the  real  clue  that 
enabled  me  to  propound  my  theory  concerning  the  phy- 
siological function  of  the  optic  thalamus,  by  applying 
to  the  physiological  interpretation  of  other  ganglions 
the  indisputable  facts  I  had  just  ascertained  respecting 
the  anterior  centre  ;  since  it  was  evident  that  what  was 
true  for  one  must  be  true  for  all  the  other  closely  related 
centres. 

Thus  by  successively  applying  the  same  processes  of 
investigation  I  arrived  at  the  following  conclusions  :  * — 

That  the  middle  centre,  so  manifestly  in  continuity, 
as  regards  its  tissue,  with  the  grey  roots  of  the  optic 
nerves,  is  destined  for  the  condensation  of  visual  im- 
pressions (Fig.  6 — 13.  14.)  ;  that  the  median  ganglion 
is  connected  with  the  condensation  of  sensitive  im- 
pressions (Fig.  6 — 8.  9.),  and  the  posterior  with  that  of 

*  I  wish  to  remark,  with  regard  to  acoustic  impressions,  that  the  acnusfic 
n'':r«'es,  as  they  are  implanted  in  the  spinal  axis,  occupy  precisely  its  most  pos- 
{ttiuc  regiors,  being  situated  behind  the  bundles  of  sensitive  fiures. 


SS  THE  BRAIN   AND   ITS   FUNCTIONS. 

auditory  impressions  (Fig.  6 — 3.  4.)  ;  and  that  thus,  in 
their  central  order  of  classification,  isolated  sensorial 
impressions  find  independent  halting-places  grouped 
along  the  same  line,  and  in  an  order  correlatively  similar 
to  that  which  presides  over  their  mode  of  distribution 
in  the  peripheral  regions  of  the  system. 

It  is,  indeed,  curious  to  observe  in  a  human  head, 
when  examined  in  profile,  that  the  olfactory  organs  of 
the  nose  are  first  met  with,  in  the  most  anterior  plane ; 
then  the  visual  organs,  the  eyes,  in  the  second  line  ;  the 
sensitive  organs  in  the  third  ;  and  finally  the  auditory 
organs,  the  ears,  occupying  the  most  posterior  place  ; 
and  that,  further,  in  their  mode  of  distribution  in  the 
central  ganglions  of  the  cerebral  mass  these  same  im- 
pressions are  grouped  in  isolated  independent  ganglions, 
occupying,  as  regards  one  another,  a  taxonomic  order, 
which  is  in  a  manner  only  a  repetition  of  their  mode 
of  origin  in  the  peripheral  regions  (20,  13.  8.  3  ; 
Fig.  6).  _ 

These  facts,  which  have  shed  quite  a  new  light  upon 
the  anatomical  and  physiological  functions  of  the  optic 
thalami,  have  found  their  confirmation,  on  the  one 
hand  in  the  experiments  of  physiology,  and  on  the 
other  hand  in  the  clinical  examination  of  symptoms, 
which  are  in  these  matters  the  irrefragable  criterion 
of  every  truly  scientific  doctrine. 

Thus  Dr.  Edouard  Fournie,  in  a  series  of  experiments 
made  on  living  animals  by  means  of  the  injection  of 
irritating  substances  into  different  parts  of  the  optic 
thalamus,  succeeded  in  annihilating  such  or  such  sen- 
sorial impressions,  according  as  the  traumatic  laceration 
had    attaci<ed    such    or   such    a  ganglion   of  the   optic 


THE  OPTIC  THALAMUS. 


39 


thalamus.     Thus  he  succeeded  in  successively  annihi- 
lating vision,  sensation,  smell,  etc.* 

On  the  other  hand,  well-observed  clinical  facts,  re- 
ported by  former  writers,  and  therefore  much  anterior 
to  my  own  researches,  showed  me  that  sometimes  sen- 
sorial impressions  might  be  totally  and  successively 
destroyed  when  the  two  optic  thalami  were  simulta- 
neously attacked,  and  that  sometimes  isolated  sensorial 
impressions  might  be  disturbed  in  consequence  of  a 
local  lesion  of  their  tissue. 

There  exists,  indeed,  a  typical  observation  made  by 
Hunter,  of  which  he  has  left  a  drawing,  which  mani- 
festly confirms  what  I  have  just  put  forward. 

In  this  observation  he  recounts  the  curious  history  of 
a  young  woman  who,  in  the  space  of  three  years, 
successively  lost  the  senses  of  smell,  sight,  hearing,  and 
sensation,  and  who  gradually  sank,  remaining  a  stranger 
to  all  external  impressions.  When  the  autopsy  of  her 
brs:in  was  made,  it  was  found  that  the  optic  thalami  of 
each  hemisphere,  and  the  optic  thalami  alone  (as  can  be 
seen  in  the  original  drawing)  f  were  attacked  by  a 
fungus  hsematodes,  which  had  progressively  destroyed 
their  substance. 

In  other  circumstances,  when  circumscribed  lesions 
have  attacked  separate  ganglions,  the  abolition  of  such 
or  such  kinds  of  sensorial  impressions  has  been  noted. 
Thus,  in  three  observations,  for  which  I  am  indebted  to 
the  kindness  of  Dr.  Auguste  Voisin,  and  in  which  the 
abolition  of  smell  on  one  side  had  been  remarked,  cor- 

*  "  Recherches  experimentals  sur  le  fonctionnement  du  cerveau,"  par  E.  D. 
Fournie,  Paris,  1873,  p,  83. 
f  "  Medico-Chir.  Transactions" — London,  1825,  vol.  xiii.  Part  Second,  p.  88. 


40  THE  BRAIN  AND   ITS   FUNCTIONS. 

responding  degenerations  of  the  anterior  centres  wert 
likewise  observed. 

In  a  case  reported  by  Serres,  in  a  man  who  bad 
suddenly  lost  the  sight  of  both  eyes,  they  found  on 
autopsy  a  haemorrhagic  effusion  occupying  the  optic 
thalamus  on  a  level  with  the  grey  commissure,  that  is 
to  say  on  a  level  with  the  middle  centres. 

In  two  unpublished  cases  observed  by  myself,  I 
noticed  a  loss  of  sensation  on  one  side  of  the  body, 
coincident  with  an  isolated  destruction  of  the  median 
centre  of  the  opposite  side. 

Finally  I  have  twice  observed,  in  the  brains  of  two 
deaf-mutes,  in  one  case  a  lesion  of  the  posterior  regions, 
in  the  other  amyloid  degeneration  of  the  same  locality 
(posterior  centres).*  On  the  theory  thus  supported  by 
the  data  furnished  by  normal  and  pathological  anatomy, 
and  experimental  physiology,  we  may,  therefore,  legiti- 
mately conclude  that  the  isolated  ganglions  of  the  optic 
thalamus  are  so  many  independent  departments  for 
each  kind  of  sensorial  impressions,  and  that  the  destruc- 
tion of  each  of  them  may  lead  to  the  disappearance  or 
alteration  of  the  function  to  which  it  is  specially 
devoted.  *!* 

2.  The  central  region  of  grey  matter  which,  as  we 
have  seen,  lines  the  internal  walls  of  the  optic  thalami, 
represents  an  elongation  into  the  brain  of  the  central 
grey  matter  of  the  spinal  cord. 

*  See  "  Annates  des  maladies  de  I'oreille  et  du  larynx,"  1875.  "  Contribu- 
tions a  I'etude  des  lesions  intra-cerebrales  de  la  surdi-mutite,"  Luys. 

t  See  the  facts  described  in  my  '  Recherches  sur  ranatomie,  la  physiologic, 
et  la  pathologie  du  systeme  nerveux,"  p.  535,  &c.,  as  complementaiy  details  on 
the  subject  of  the  symptoms  determined  by  different  lesions  of  the  optic 
thalami. 


THE  OPTIC   THALAMUS.  4I 

It  presents  the  appearance  of  two  tracts  of  ashen- 
grey  matter,  which  here  and  there  form  protuberances, 
which  are  themselves  individually  connected  with 
the  nerve-fibrils  which  are  implanted  in  them.  Such 
are  the  grey  protuberances  of  the  septum,  for  the 
internal  olfactory  roots  ;  those  of  the  tuber  cinereiLm, 
for  the  optic  fibres  ;  the  mamillary  tubercles  and  pineal 
gland,  for  the  connecting  fibres  emanating  from  the 
anterior  centres. 

It  similarly  receives  a  certain  contingent  of  grey 
ascending  fibres,  which  probably  represent  the  centripetal 
spinal  fibres  which  are  distributed  in  these  plexuses.* 

The  central  grey  matter  is  composed  of  a  network  of 
anastomosing  cells,  forming  a  continuous  plexus. 

Since,  on  the  other  hand,  we  can  demonstrate  that 
the  white  cerebral  fibres  radiating  from  the  convolutions 
do  not  all  lose  themselves  in  the  small  centres  of  the 
optic  thalamus,  but  that  a  certain  number  of  them, 
pursuing  their  primitive  direction,  are  prolonged  as  far 
as  the  plexuses  of  the  central  grey  matter,  we  may 
legitimately  recognize  in  this  anatomical  arrangement 
the  natural  channel  for  the  propagation  of  nervous 
actions  emanating  from  the  cortical  periphery,  and 
manifesting  themselves  in  the  plexuses  of  central  grey 
matter ;  and  reciprocally,  interpreting  things  in  an 
inverse  sense,  we  may  recognize  in  this  species  of 
nerve-fibres  the  direct  means  of  communication  between 
the  spheres  where  the  phenomena  of  vegetative  life  take 
place,  and  those  regions  of  the  cortical  substance  which 
are  the  theatre  of  psycho-intellectual  activity. 

To  sum  up,  the  optic  thalami  are  in  a  special  manner 

•  See  Luys'  "  Iconographie  des  centres  nerveux."     Plate  65. 

5 


42  THE  BRAIN   AND   ITS   FUNCTIONS. 

the  natural  anatomical  foci  which  preside  over  the 
organization  and  grouping  of  the  cerebral  fibres.  From 
a  physiological  standpoint,  the  optic  thalami  are  inter- 
mediary regions  interposed  between  the  purely  reflex 
phenomena  of  the  spinal  cord  and  the  activities  of 
psychical  life. 

By  their  isolated  and  independent  ganglions  they 
serve  as  points  of  condensation  for  each  order  of  sensorial 
impressions  that  finds  in  their  network  of  cells  a  place  of 
passage  and  a  field  for  transformation.  It  is  there  that 
these  are  for  the  first  time  condensed,  stored  up 
and  elaborated  by  the  individual  metabolic  action 
of  the  elements  that  they  disturb  in  their  passage.  It 
is  thence,  as  from  a  penultimate  stage,  that,  after  having 
passed  through  ganglion  after  ganglion,  along  the 
centripetal  conductors  which  transport  them,  they  are 
launched  forth  into  the  different  regions  of  the  cortical 
periphery  in  a  new  form — intellectiialized  in  some  way, 
to  serve  as  exciting  materials  for  the  activity  of  the 
cells  of  the  cortical  substance.     (Fig.  6 — 14.  9.  4.) 

These  are,  then,  the  soL  and  unique  open  gates  by 
which  all  stimuli  from  without,  destined  to  serve  as, 
pabulum  vitcz  for  these  same  cortical  cells^  pass ;  and  the 
only  means  of  communication  by  which  the  regions  of 
psychical  activity  come  into  contact  with  the  external 
world.* 

*  From  the  intimate  connexions  which  unite  the  plexuses  of  the  optic 
thalamus  with  those  of  the  cortic:il  layer,  and  which  cause  these  latter,  as  regards 
the  evoking  of  their  activity,  to  be  complete!}' dependent  upon  the  materials 
transmitted  to  fhem,  it  may  be  understood  what  an  important  part  the  morbid 
activity  of  the  plexuses  of  the  optic  thalami  may  play  in  the  evolution  of  various 
hallucinatory  processes.  See,  for  compleirentary  details  on  the  importance  of 
irritations  of  the  optic  thalami  in  the  development  of  hallucinations,  the 
inaugural  thesis  of  Dr.  Ritti.     Pa. is,  1874. 


THE  OPTIC   THALAMUS.  43 

On  the  other  hand,  a  direct  examination  of  the 
relations  of  the  centres  of  the  optic  thalami  to  the 
different  regions  of  the  cortical  periphery  enables  us  to 
determine  the  following  peculiarities  also. 

It  is  sufficient  to  cast  a  glance  over  horizontal  sections 
of  the  brain  to  recognize  that  each  of  these  centres  is 
more  particularly  in  connection  with  certain  regions  of 
this  very  cortical  substance.  Thus,  for  instance,  we  see 
plainly  that  the  central  ganglion,  by  means  of  the  white 
fibres  that  emerge  from  it,  apparently  radiates  the 
impressions  it  condenses  towards  the  antero-lateral 
regions  of  the  brain,*  and  that  the  posterior  centre 
acts  in  the  same  manner  as  regards  the  regions  of  the 
posterior  cormia  ;  while  the  median  centre,  by  means  of 
the  divergent  fibrils  which  are  implanted  in  its  mass, 
appears  to  direct  its  radiations  indifferently  towards 
all  parts  of  the  cortical  substance.  The  anterior  centre, 
less  distinctly  attached  to  the  cortical  substance,  seems, 
nevertheless,  to  have  its  special  area  of  distribution 
in  the  grey  matter  of  the  hippocampus.  In  the  animal 
species  in  which  the  olfactory  organs  are  well  developed, 
this  convolution  similarly  exhibits  a  high  degree  of 
development. 

These  anatomical  data,  which  every  one  can  observe, 
de  visu,  throw  a  completely  new  light  upon  that  long- 
discussed  question  as  to  cerebral  localizations,  and  are 
direct  evidence  that  there  are  in  the  different  regions  of 
the  cortical  substance  isolated  circumscribed  localities, 
affected  in  an  independent  manner,  for  the  reception  of 
such  or  such  kinds  of  sensorial  impressions.     We  are 

*  See  my  "  Inconographie  photographique  des  centres  nerveux."  Plates  iv. 
V.  vi. 


44  THE  BRAIN   AND   ITS   FUNCTIONS. 

thus  logically  led  to  comprehend  that  the  peripheral 
development  of  such  or  such  a  sensory  organ  is 
designed  to  have  a  receptive  organ  in  some  way 
adapted  to  it  in  the  central  regions,  and  that  the  rich- 
ness in  nerve-elements  of  such  or  such  a  region  of 
the  cortical  substance  itself,  and  the  degree  of  proper 
sensibility  and  specific  energy  of  each  of  them,  may,  at 
a  given  moment,  play  an  important  part  in  the  sum 
total  of  mental  faculties,  and  thus  determine  the  tem- 
perament of  the  specific  activity  of  such  or  such  an 
organization. 

We  thus  recognize  the  fact  that  the  secret  of  certain 
aptitudes — of  such  or  such  a  native  predisposition,  is 
naturally  derived  from  the  preponderance  of  such  or 
such  a  group  of  sensorial  impressions,  which  find  in  the 
regions  of  psychical  activity  in  which  they  are  particu- 
larly elaborated  a  soil  ready  prepared,  which  amplifies 
and  perfects  them  according  to  the  richness  and  degree 
of  vitality  of  the  elements  placed  at  their  disposal. 

Finally,  the  plexuses  of  the  central  grey  mattery  which 
are  similarly  united  to  the  difi"erent  regions  of  the 
cortical  substance,  show  us  that  stimuli  radiated  from 
the  depth  of  visceral  life  ascend,  with  the  organic  tissue 
which  carries  them,  as  far  as  the  interior  of  the  brain* 
(the  experiments  of  SchifT  confirm  this) ;  and  that  they 
are  thus  carried  into  the  diff"erent  regions  of  the  cortical 
substance,  and  associated  with  the  essential  phenomena 
of  psychical  activity. 

From  this  double  induction  we  are  therefore  led  to 

*  The  experiments  of  Schiff  tend  to  show  that  the  vascular  nerves  of  the 
liver  and  stomach  pass  over  the  medulla  oblongata  to  terminate  higher  up. 
"A  portion  of  them,"  he  says,  "appears  to  reach  the  optic  thalamus," 
("  Couipie  rendu  de  I'acad^mie  des  sciences,"  T5th  Sept.,  1862.) 


THE   OPTIC  THALAMUS.  45 

consider  the  masses  of  grey  matter,  usually  described 
under  the  name  of  optic  thalami,  as  essentially  central 
regions  which  are  the  bond  of  union  between  the  various 
elements  of  the  entire  cerebral  system. 

Through  their  tissues  pass  vibrations  of  all  kinds, 
those  which  radiate  from  the  external  world,  as  well  as 
those  which  emanate  from  vegetative  life.  There,  in  the 
midst  of  their  cells,  in  the  secret  chambers  of  their  pecu- 
liar activity,  these  vibrations  are  diffused,  and  make  a 
preparatory  halt ;  and  thence  they  are  darted  out  in  all 
directions,  in  a  new  and  already  more  animalized  and 
more  assimilable  form,  to  afford  food  for  the  activity 
of  the  tissues  of  the  cortical  substance,  which  only  live 
and  work  under  the  impulse  of  their  stimulating  excite- 
ment. 


CHAPTER  V. 

THE  CORPUS   STRIATUM.* 

The  mass  of  grey  matter  designated  by  the  name  of 
corpus  striatum  is  the  complement  of  the  optic  thalamus, 
with  which  it  constitutes  those  two  grey  ganglions  which 
occupy  the  central  region  of  each  hemisphere,  and 
which  are,  as  has  been  frequently  pointed  out,  the 
natural  poles  around  which  all  the  nervous  elements 
gravitate. 

While  the  optic  thalami  present,  in  a  manner,  masses 
of  grey  matter  grouped  around  the  prolongation  of  the 
posterior  columns  of  the  spinal  axis,  of  which,  speaking 
in  general  terms,  they  form  the  crown,  the  corpora  striata 
are,  on  the  contrary,  situated  on  the  prolongation  of  the 
antero-lateral  columns.  They  therefore  evidently  occupy 
an  anterior  situation  as  regards  the  optic  thalami  ;  and 
in  connection  with  this  subject,  it  is  not  without  interest 
to  remark  that  the  same  relations  that  exist  in  the  whole 
of  the  spinal  cord,  are  here  reproduced  with  obviously 
analogous  characteristics. 

In  the  cord  the  sensitive  or  excito-motor  regions 
occupy  the  posterior  portion,  while  the  essentially  motor 
regions  occupy  the  anterior. 

In  the  brain  the  same  relations  as  to  neighbourhood, 

*  Fig.  6,  p.  6i,  and  Fig.  5,  p.  31. 


THE  CORPUS  STRIATUM.  47 

and  the  same  correlative  arrangements  exist.  Indeed, 
while  the  optic  thalami  with  their  different  ganglions  re- 
present the  regions  of  passage  for  sensorial  impressions, 
the  grey  matter  of  the  corpora  striata,  with  its  multiple 
elements,  represents  the  place  of  halt  and  reinforcement 
for  motor  stimuli  radiating  from  the  cerebral  cortex. 

It  may  therefore  be  said  that  in  the  brain,  by  virtue  of 
the  same  anatomic  arrangements,  the  regions  where  the 
phenomena  of  sensation  occur,  and  those  in  which 
motor  stimuli  are  elaborated,  reciprocally  maintain 
the  same  topographic  relations  that  they  have  in  the 
different  portions  of  the  spinal  cord  proper. 

As  to  external  configuration  the  mass,  of  the  corpus 
striatum  presents  the  form  of  a  reddish  grey  mass,  of 
flabby  consistence*,  situated  in  front  of  the  optic 
thalamus,  and,  gradually  diminishing  from  before  back- 
wards, extending  as  far  as  its  posterior  regions. 

It  follows  that  the  mass  of  the  corpora  striata  pre- 
sents an  ovoid  pyriform  appearance,  the  larger  extremity 
directed  forwards,  the  tapered  extremity  backwards, 
and  that  the  optic  thalamus  in  its  antero-lateral  regions 
is  encircled  with  a  network  of  grey  substance  having  its 
maximum  thickness  anteriorly. 

It  follows  besides,  as  a  consequence  of  this  anato- 
mical arrangement,  that  the  white  converging  fibres 
which  group  themselves  around  the  optic  thalamus, 
before  arriving  at  their  destination  encounter  a  more 

*  This  soft  consistence  of  the  grey  matter  of  the  corpus  striatum,  on  the 
one  hand,  and  the  excessive  development  of  the  capillaries  which  circulate  in 
its  mass  on  the  other,  explain  the  extreme  friability  of  its  tissue  and  the 
facility  with  which  it  may  be  lacerated  by  congestions  which  render  the  vessels 
turgid.  Thus  we  may  account  lor  tht;  greater  frequency  of  unilateral  paralysof 
of  motion,  as  compared  with  those  of  sensation. 


48  THE  BRAIN   AND   ITS   FUNCTIONS. 

or  less  considerable  thickness  of  the  corpus  striatum, 
which  they  traverse  from  one  side  to  the  other,  at 
various  angles  and  in  various  directions.  (Fig.  5.)  The 
anterior  convergents  in  particular,  which  run  towards 
the  corresponding  regions  of  each  optic  thalamus, 
plunge  from  before  backwards  into  the  very  mass  of  the 
corpus  striatum,  and  divide  it  into  two  segments,  one 
extra-  and  one  intra-ventricular.* 

The  colour  of  the  grey  matter  of  the  corpus  striatum 
is  sensibly  homogeneous,  wherever  it  is  observed.  It  is 
flabby,  reddish,  and  composed  of  special  anatomical 
elements.  It  is,  moreover,  permeated  by  an  infinite 
number  of  whitish  serpentine  filaments,  which  represent 
the  terminal  expansions  of  the  antero-lateral  motor 
fibres  of  the  spinal  cord. 

In  the  internal  and  inferior  regions,  however,  where 
there  is  a  confluence  of  all  the  antero-lateral  fascicles  of 
the  spinal  axis  which  expand  into  the  corpus  striatum, 
we  come  upon  a  very  clearly  circumscribed  region  of 
firmer  consistence,  and  yellowish  colour,  which  is  easily 
recognized  by  its  peculiar  striation.-[- 

This  peculiar  circumscribed  mass  of  yellowish  matter, 
which  I  have  more  particularly  designated  under  the 
name  oi  yellow  nucleus  of  the  corpus  striatum,  plays 
an  important  part,  as  a  centre  of  radiation  for  nerve- 
fibres,  in  its  relations  with  the  ultimate  expansions  of 
the  cerebellar  peduncles. 

*  These  are  ihose  fibres  composed  of  isolated  fascicles  regularly  stratified 
one  above  the  other,  of  which  the  continuity  may  be  clearly  ascertained  by 
tlie  aid  of  dissection,  in  antero-posterior  sections  of  the  brain.  They  are 
most  improperly  designated  by  the  name  of  the  internal  capsule.  {See  ' '  Icono- 
graphie  photographique,"  pi.  xlv.) 

t  See  "  Iconographie  photographique,"  pi.  xxxi.  xxxii.  x.  xi.  xliii.  and  xliv. 


THE   CORPUS   STRIATUM.  49 

The  structure  of  the  corpus  striatum  must  now  be 
considered,  as  regards  : 

1.  The  study  of  the  grey  matter,  regarded  from  a  his- 
tological point  of  view,  and  as  to  the  characteis  of  its 
elements. 

2.  That  of  the  nervous  elements,  of  various  origin, 
which  enter  into  relation  with  those  proper  to  itself. 

I.  The  grey  matter  of  the  corpus  striatum  is  histo- 
logically composed  of  an  infinite  number  of  large  poly- 
gonal nerve-cells  with  multiple  prolongations,  their  size 
being  in  general  about  the  same  as  that  of  the  larger 
ceils  of  the  cerebral  cortex.  These  cells,  considered 
in  themselves,  present  characters  common  to  all  the 
other  cells.  They  are  provided  with  what  appear  to  be 
a  nucleus  and  nucleolus,  and  present  ramified  prolon- 
gations which  rapidly  taper  away,  and  constitute  with 
those  of  the  neighbouring  cells  a  very  dense  and  very 
delicate  network. 

Besides  these  large  cells  just  mentioned,  we  also 
meet  with  elements  of  smaller  size,  especially  in  the 
region  of  the  yellow  nuclei,  where  they  are  extremely 
abundant.  Their  histological  characters  recall  in  a  more 
or  less  vivid  manner  the  similar  elements  met  with  in 
the  deep  zones  of  the  grey  matter  of  the  cerebellar  con- 
volutions. These  small  elements,  of  which  the  nucleus 
is  voluminous,  and  of  which  the  yellowish  colour  enables 
us  to  distinguish  them  from  the  surrounding  corpuscles 
of  the  neuroglia,  exhibit  a  fringe  of  radicles  of  extreme 
tenuity,  which  is  lost  in  the  network  formed  by  the 
large  cells.  It  seems,  then,  probable  that  these  small 
cells,  which  to  some  extent  histologically  represent  the 
cerebellar  e^lement,  enter  more  or  less  directly  into  co.n- 


50  THE   BRAIN  AND   ITS   FUNCTIONS. 

bination  with  the  radiations  from  the  large  cells  which 
represent  the  cerebral  element. 

Besides  these  two  principal  elements,  we  have  still  to 
describe  the  corpuscles  of  neuroglia,  derived  more  or 
less  directly  from  the  sheaths  of  the  capillaries,  and  a 
considerable  number  of  vessels  which  directly  penetrate 
from  below  upwards  into  its  interior  in  the  form  of  more 
or  less  rectilinear  filaments.  (Perforated  space  of  Vicq 
d'Azyr.) 

2.  The  diverse  elements  which  enter  into  the  anatomic 
constitution  of  the  corpus  striatum,  are  divided  into  two 
special  groups  :  I,  some  may  be  considered  as  a  system 
of  fibres  afferent  to  the  corpus  striatum  ;  2,  others  as 
a  system  of  efferent  fibres. 

I.  The  first  group  comprehends :  «f,  on  the  one 
hand,  all  the  cerebral  fibres  radiating  from  the  different 
regions  of  the  cortex,  and  lost  in  the  substance  of  the 
corpus  striatum  (cortico-striate  fibres)  ;  /3,  on  the  other 
hand  the  ultimate  expansions  of  the  superior  cerebral 
peduncles,  which  are  lost  in  its  mass,  and  which  repre- 
sent the  specific  importation  of  the  cerebellar  element 
into  the  constitution  of  motor  phenomena. 

a.  (Fig.  6 — 6.  II.  1 6.)  The  elements  of  the  first  group, 
which,  on  account  of  their  origin  and  termination,  I  have 
proposed  to  call  cortico-striate,  belong  to  that  mass  of 
convergent  fibres  which,  radiating  from  all  points  of  the 
cortical  periphery,  and  probably  from  the  psycho-motor 
regions  so  clearly  determined  at  the  present  day,  take  a 
common  direction  towards  the  central  ganglions.  This 
order  of  fibres,  however,  once  arrived  at  the  circumference 
of  the  optic  thalamus,  instead  of  terminating  like  their 
fellows,  only  embrace  it.     Arrived    at   the  frontier   of 


THE  CORPUS   STRIATUM.  5  I 

the  optic  thalami  and  the  corpora  striata,  these  fibre:; 
are  immediately  reflected  from  below  upwards,  in  the 
form  of  spiroid  lines,  and  are  finally  isolatedly  dis- 
tributed in  the  different  cell-territories  of  the  corpus 
striatum  with  which  they  are  especially  connected. 

These  cortico-striate  fibres,  which  have  come  out  of 
the  depths  of  the  cortical  layer  with  the  sensitive  fibres, 
still  proceed  for  a  certain  distance  through  the  brain,  in 
juxtaposition  with  these  latter,  as  is  also  the  case  in  the 
peripheral  nervous  trunks,  which  are  composed  of  both 
sensitive  and  motor  fibres,  embraced  in  the  same 
envelope.  Soon,  having  arrived  in  the  presence  of 
their  respective  centres  of  attraction,  they  each  obey 
their  innate  affinities,  and  are  distributed,  some  to  the 
centres  of  the  optic  thalamus,  others  to  the  different 
regions  of  the  grey  substance  of  the  corpus  striatum. 

These  fibres  then  represent,  properly  speaking,  the 
natural  bonds  of  union  between  the  regions  of  the 
cortical  substance  whence  proceed  the  different  volun- 
tary stimuli  (psycho-motor  centres),  and  the  different 
cell-territories  of  the  corpus  striatum  where  they  are 
reinforced.  As  regards  anatomical  analogies,  they 
represent  the  whole  group  of  anterior  roots  in  its 
relations  with  the  grey  elements  of  the  spinal  cord. 

Their  precise  origin  in  the  different  regions  of  the 
cortical  periphery  is  still  a  problem  to  be  solved  for 
each  of  them  in  particular.  (Fig.  6 — 6.  ii.  i6.)  This  is 
also  the  case  as  regards  their  central  distribution  in  the 
different  cell-territories  of  the  corpus  striatum.  (2.  12. 
17 — Fig.  6.)  At  the  present  day  they  are  only  known 
and  anatomically  demonstrable  in  an  intermediate  por- 
tion   of  their   transit,   at   the   moment  when  they  are 


52  THE  BRAIN   AND   ITS   FUNCTIONS. 

reflected  in  the  form  of  serpentine  fibres  ;  *  and  yet 
their  existence,  as  centrifugal  conductors  of  motor 
stimuli,  radiating  from  the  excitable  zones  of  the  cere- 
bral cortex,  is  very  clearly  demonstrated.  This  is  one 
of  the  most  interesting  points  that  experimental  physio- 
logy has  brought  to  light  in  recent  times. 

The  recent  researches  of  Fritsch  and  Hitzig,  who 
were  the  first,  in  1870,  to  point  out  that  certain  zones 
of  the  grey  cortex  were  excitable  by  galvanic  currents,t 
have  opened  the  road  in  this  direction.  J  Ferrier  has 
shown,  indeed,  after  them,  that  by  applying  electric 
excitement  in  such  or  such  a  region  of  the  grey  cortex, 
motor  reactions  in  such  or  such  isolated  groups  of 
muscles  are  determined  ;  that  at  will  we  may  cause  the 
eyes,  tongue,  neck,  etc.,  of  an  animal  to  move,  according 
as  we  electrify  such  or  such  a  convolution  ;  and  that, 
in  a  word,  there  are  in  the  tissue  of  the  cortical  layer 
a  series  of  small  independent  motor  centres,  which 
may  be  isolatedly  excited,  and  which  communicate  by 
independent  conductors  with  the  different  portions  of  the 
muscular  system.  More  than  this,  it  has  been  proved 
that  things  take  place  in  the  same  manner  in  man  ; 
tor  an  American  physician,  pushing  the  boldness  of 
experiment  to  its  ultimate  limits,  obtained  similar 
results  in  a  patient  whose  brain  was  denuded  by  a 
degeneration  of  the  cranial  case.§ 

*  See  "  Iconographie  photographique,"  pi.  xxxii.  and  xxxiv. 

•f-  "Archivof  du  Bois-Reymond,"  (1870,  Heft.  3). 

X  See  "  Progres  medical,"  number  28,  1873,  and  number  i,  1874.  "  Re- 
clierches  experimenlales  sur  la  physiologic  et  la  pathologie  c^r^brales,"  by 
Ferrier. 

g  See  the  "Movement  medical,"  1874,  number  33,  pi.  381.  "  Recherches 
exp^rinientales  sur  les  fonctions  du  cerveau  humain,'  by  Robert  Bartholow, 
Professor  in  the  Medical  College  of  Ohio. 


THE   CORPUS   STRIATUM.  53 

Finally,  in  certain  pathological  cases  in  which  I 
made  special  researches,  still  unpublished,  I  have  even 
been  able  to  demonstrate,  as  a  proof  of  the  exist- 
ence in  the  cortical  layer  of  isolated  foci  of  motor 
excitation,  that  in  persons  who  had  undergone  amputa- 
tions at  a  distant  date — subjects  who  had  been  long 
deprived  of  an  upper  limb,  in  the  case  of  disarticulation 
of  the  shoulder,  for  instance — there  existed  in  certain 
long  disused  regions  of  the  brain,  coincident,  very  dis- 
tinctly localized  atrophies.  I  have,  moreover,  demon- 
strated that  the  atrophied  regions  of  the  brain  are  not 
the  same  in  the  case  of  the  amputation  of  a  leg,  and  in 
that  of  amputation  of  the  upper  limbs. 

These  facts,  then,  as  I  have  already  explained  in  former 
works,  already  extending  over  ten  years,  authorize 
us  to  conclude  that  there  exists  a  special  order  of 
nerve-fibres  radiating  from  different  departments  of  the 
cortical  substance,  and  distributed  in  isolated  territories 
of  the  grey  matter  of  the  corpus  striatum,  which  is 
thus  associated  as  a  co-operant  factor  in  all  the  vibra- 
tions that  take  place  in  the  plexuses  of  cerebral  cells  ; 
and  to  consider  it  as  proved  that  these  different  groups 
of  cortico-striate  fibres  have  each  an  independent  point 
of  origin. 

/3.  The  afferent  element";  of  the  second  group,  as  we 
have  already  indicated,  are  represented  by  the  terminal 
expansions  of  the  cerebellar  peduncles. 

The  superior  cerebellar  peduncles,  in  fact,  after  inter- 
crossing in  the  median  line,  become  associated  and  form 
two  masses  of  grey  matter,  described  by  Stilling,  and 
recognizable  by  their  reddish  colour. 

These  two  ganglions,  which,  as  regards  their  structure 


54  THE  BRAIN  AND  ITS   FUNCTIONS. 

and  connections  represent  a  veritable  focus  of  radiation 
for  cells  and  nerve-fibres,  give  rise  throughout  all  their 
antero-external  substance  to  a  series  of  fibrils,  inter- 
laced in  a  thousand  ways,  which  all  terminate  in  the 
form  of  yellowish  filaments,  in  the  grey  matter  of  the 
corpus  striatum.  It  is  this  special  contingent — an  in- 
direct emanation  from  the  active  elements  of  the  cere- 
bellum— that  gives  to  this  particular  department  of  the 
corpus  striatum,  that  characteristic  yellowish  colour, 
which  I  have  already  described  under  the  name  of  the 
yellow  nucleus  of  the  corpus  striatum. 

These  fibrils  of  cerebellar  origin  which  are  disposed  in 
the  form  of  yellowish  rayed  filaments,  taper  away  insen- 
sibly, and  embrace  the  white  spinal  fibres  which  expand 
in  the  corresponding  regions  of  the  corpus  striatum  ; 
and  are  probably  lost  in  the  network  of  large  cells,  as 
has  been  previously  suggested. 

Now,  how  do  they  terminate  }  What  is  the  ultimate 
mode  of  combination  of  the  individual  elements  which 
represent  in  the  brain  the  activity  of  the  cerebellum  ? 
How  does  the  cell  of  the  corpus  striatum  come  into 
contact  with  the  cerebellar  elements  of  the  new 
importation  ? 

So  far  I  have  only  been  able  to  form  conjectures,  and 
while  supposing  that  there  must  be  some  sort  of  ana- 
tomic combination  between  these  elements  of  varied 
origin,  I  can  only  pause  and  await  the  results  of  future 
researches. 

However  it  may  be,  we  cannot  help  considering  the 
corpus  striatum,  from  a  dynamic  point  of  view,  as  being 
indirectly  connected  with  the  phenomena  of  cerebellar 
activity,  and  seeing  in  the  superior  cerebellar  peduncles, 


THE   CORPUS   STRIATUM.  55 

in  the  red  ganglions  of  Stilling,  and  in  the  yellowish 
radii  which  emerge  from  them,  so  many  centrifugal 
conductors,  incessantly  active  foci  of  nervous  radiation, 
which  allow  the  cerebellar  motor  influences  with  which 
they  are  charged  to  overflow  into  these  plexuses. 

The  cerebellar  innervation,  is  thus  intimately  asso- 
ciated with  the  vital  phenomena  of  the  corpus  striatum  as 
a  true  auxiliary  force.  It  is  incessantly  overflowing  into 
its  thousand  plexuses  like  a  continuous  current  of  electric 
force,  and,  as  it  were,  charges  its  nerve-cells.  In  motor 
phenomena  it  is  associated  with  all  our  difl"erent  motor 
acts,  and  gives  to  our  movements  their  regularity,  their 
force,  and  their  continuity.  Under  a  thousand  forms,  in 
fact,  it  silently  disperses  itself  through  all  the  conscious 
and  unconscious  actions  of  the  organism,  and  seems  to 
be  an  indispensable  component  of  every  motor  act 
whatsoever.* 

2.  The  elements  of  the  second  group,  those  which 
constitute  the  mass  of  the  efferent  fibres  of  the  corpus 
striatum,  are  represented  by  that  series  of  nerve-fibres 
which  are  ordinarily  described  under  the  name  of 
cerebral  peduncles,  and  which,  grouped  in  the  form  of 
isolated  fascicles,  and  arranged  in  a  spiroid  fashion, 
pass  in  succession,  after  having  traversed  the  pons,  to  be 
dispersed  in  the  difl"erent  segments  of  the  spinal  axis. 
These    fibres,   which   represent   conductors   interposed 

*  The  researches  of  experimental  physiology,  as  well  as  clinical  phenomena, 
rtenionstrate  in  an  unmistakable  manner,  the  important  part  played  by 
cerebellar  innervation  in  motor  acts.  When  the  cerebellum  is  engaged  in 
Rny  way,  disturbances  in  the  regular  co-ordination  of  movements  are  always 
perceived,  and  more  than  this,  motor  acts  are  weakened,  a  phenomenon  of 
the  utmost  importance,  as  implying  the  extinction  of  the  foci  of  motor 
innervation  which  are  designed  to  produce  theai. 


$6  THE  BRAIN   AND   ITS   FUNCTIONS. 

between  the  difTerent  cell-territories  of  the  corpus 
striatum  and  the  different  ganglions  of  the  motor  nerves 
of  the  spinal  chord,  are  not  distinctly  isolated  at  their 
point  of  origin  in  the  plexuses  of  cells  of  the  corpus 
striatum.  (Fig.  6. — 12.  12'.  17  and  19.) 

All  that  we  can  say  of  them  is,  that  they  appear  by 
insensible  degrees  in  the  form  of  whitish  traces  creeping 
over  the  grey  matter  of  the  extra-  and  intra-ventricular 
ganglions  ;  that  soon  they  insensibly  increase  in  volume; 
that  converging  like  the  rays  of  a  fan,  they  all  approach 
the  yellow  nuclei  of  the  corpus  striatum  ;  that  they 
gradually  enter  into  contact  with  the  yellow  fibres  which 
constitute  the  substance  of  these  bodies  ;  and  that  when, 
after  condensation,  they  emerge  from  the  corpus  striatum, 
they  present  themselves  in  the  form  of  three  demi- 
cones,  one  enclosing  the  other.     (Fig.  6. — 19.)* 

These  nervous  elements,  having  been  thus  arranged 
and  reinforced  by  the  union  of  different  masses  of 
grey  matter  belonging  to  the  cerebellar  innervation 
(grey  matter  of  Sommering,  grey  matter  of  the  po/is) 
(Fig.  6. — 18.  19.  T9'.  19")  pursue  a  descending  and 
oblique  course,  which  causes  them  (on  a  level  with  the 
medulla)  to  pass  insensibly  into  the  opposite  regions  of 
the  spinal  axis.  Little  by  little,  and  fascicle  by  fascicle, 
they  separate,  to  distribute  themselves  in  the  different 
segments  of  the  spinal  cord,  and  in  the  different  groups 
of  motor  cells  of  the  antero-lateral  regions.  These, 
regularly  stratified  one  above  another,  like  a  series  of 
electric  machines    always    ready  to  start    into   action, 

*  In  a  horizontal  section  of  this  region,  these  three  demi-cones  present  the 
appearance  of  three  semicircular  concentric  lines,  '^ee  "  Iconographie  i>hoto- 
graphique,"  pi.  xi.  and  xxxi.,  fig.  x. 


THE   CORPUS   STRIATUM.  57 

silently    await    the    arrival    of   the    stimulating   spark 
destined  to  call  them  into  activity. 

Thus  it  follows,  from  what  we  have  just  explained, 
that  the  corpus  striatum,  like  the  optic  thalamus,  is  a 
nervous  apparatus  with  multiform  activities. 

It  is  a  common  territory  into  which  the  cerebral,  cere- 
bellar, and  spinal  activities  come  in  succession,  to  be 
combined,  and  I  might  almost  say,  to  anastomose. 
It  thus  represents,  from  a  dynamic  point  of  view,  a 
synthesis  of  multiple  elements. 

It  is  in  the  midst  of  its  tissues  that  the  influence 
of  volition  is  first  received  at  the  moment  when  it 
emerges  from  the  depths  of  the  psycho-motor  centres 
of  the  cerebral  cortex.  There  it  makes  its  first  halt 
in  its  descending  evolution,  and  enters  into  a  more 
intimate  relation  with  the  organic  substratum  destined 
to  produce  its  external  manifestations — in  one  word, 
materializes  itself.     (Fig.  6. — 12  and  17.) 

From  this  moment  it  comes  into  intimate  contact 
with  the  innervation  radiating  from  the  cerebellum,  and 
it  is  now  no  longer  itself,  no  longer  the  simple  purely 
psycho-motor  stinlulus  it  was  at  its  origin.  It  is  asso- 
ciated with  this  new  influence,  which  gives  it  somatic 
force  and  continuity  of  action.  It  then  passes  out  of 
the  brain  by  means  of  the  peduncular  fibres,  combined 
with  a  new  element,  and  pursuing  its  centrifugal  course, 
it  is  finally  extinguished  here  and  there  by  setting  in 
motion  the  difl"erent  groups  of  cells  of  the  spinal  axis, 
whose  dynamic  properties  it  thus  evokes.  (Fig.  6. — 18 
and  19.) 

Thus  also,  proceeding  like  an  electric  current  into  the 
different   departments    it   animates,  it    now    tends    to 
6 


58  THE   BRAIN   AND   ITS   FUNCTIONS. 

produce  phono-motor  movements  designed  to  express 
outwardly  the  emotions  of  our  sentient  personality,  and 
now  to  determine  in  the  different  muscular  groups, 
general  or  partial  movements  of  flexion,  extension,  or 
progression,  according  as  it  is  distributed  to  such  or 
such  groups  of  satellite  cells,  the  habitual  servants  of  its 
excito-motor  demands. 

We  see  then,  to  sum  up,  by  means  of  this  simple 
physiological  sketch,  what  an  all-important  part  these 
two  central  ganglions  play  in  the  phenomena  of  cere- 
bral activity,  and  how  completely  different  is  the 
mode  of  action  of  each. 

The  elements  of  the  optic  thalami  purify  and  trans- 
form by  their  peculiar  metabolic  action  impressions 
radiating  from  without,  w^hich  they  launch  in  an  intel- 
lectualized  form  towards  the  different  regions  of  the 
cortical  substance.  The  elements  of  the  corpus 
striatum,  on  the  contrary,  have  an  inverse  influence 
upon  the  stimuli  starting  from  these  same  regions  ot 
the  cortical  substance.  They  absorb,  condense, 
materialize  them  by  their  intervention  ;  and,  having 
amplified  and  incorporated  them  more  and  more  with 
the  organism,  they  project  them  in  a  new  form  in  the 
direction  of  the  different  motor  ganglions  of  the 
spinal  axis,  where  they  thus  become  one  of  the  multiple 
stimulations  destined  to  bring  the  muscular  fibre  into 
play. 


CHAPTER  VI. 

PHYSIOLOGICAL  DEDUCTIONS. 

Now,  if  we  group  synthetically  the  anatomical  pro- 
positions we  have  tried  to  establish  in  the  course  of 
this  work,  we  see  that  the  brain  is  a  geminate  organ, 
formed  of  two  hemispheres,  of  which  the  elements  are 
strictly  associated  with  one  another,  by  means  of  a 
series  of  commissural  fibres  which  unite  them  in- 
timately, and  produce  a  certain  tendency  in  their  mole- 
cules to  vibrate  in  unison.     (Figs.  3.  and  4.) 

Each  of  these  two  lobes,  or  hemispheres,  is  funda- 
mentally formed  of  masses  of  grey  matter  irregularly 
distributed — the  grey  matter  of  the  central  ganglions 
(the  optic  thalami  and  corpora  striata)  and  that  of  the 
cerebral  cortex. 

These  two  regions  of  cerebral  activity  are  united  to 
one  another  by  a  series  of  white  fibres,  which  serve  as  a 
bond  of  union  between  them,  and  as  a  channel  of  pro- 
pagation for  nervous  currents  passing  from  one  to  the 
other,  either  centrifugally  or  centripetally. 

The  opto-striate  central  ganglions  of  each  lobe  may 
be  ideally  conceived  as  occupying  the  centre  of  a  hollow 
sphere,  of  which  the  circumference  is  represented  by 
the  undulations  of  the  cerebral  cortex  ;  and  the  white 
fibres  v/ould  thus  represent  an  infinite  number  of  radii 


60  THE  BRAIN   AND   ITS   FUNCTIONS. 

uniting  the  central  with  the  peripheral  regions  of  the 
sphere.     (Fig.  5.) 

The  anatomical  study  which  we  have  just  made,  of 
the  grey  matter  of  the  optic  thalamus  and  that  of  the 
corpus  striatum,  has  enabled  us  to  observe  distinct 
differences  between  them,  and  consequently  to  formu- 
late the  unlike  dynamic  aptitudes  with  which  each  of 
these  two  ganglions  is  gifted. 

We  have  thus  seen  that  the  function  of  the  optic 
thalamus  in  particular  seems  to  be  that  of  receiving,  con- 
densing, and  transforming,  like  a  true  nervous  ganglion, 
impressions  radiating  from  the  sensorial  periphery,  before 
launching  them  into  the  different  regions  of  the  coriical 
substance  ;  and  that,  inversely  (Fig.  6. — 14,  9.  4.),  the 
corpus  striatum,  in  connection  with  exclusively  motor 
regions,  appears  to  be  a  place  of  passage  and  rein- 
forcement for  stimuli  radiating  from  the  different 
psycho-motor  zones  of  the  cortical  periphery. 

These  anatomical  connections  being  admitted  as  fun- 
damental datUy  as  regards  the  structure  and  mode  of 
agency  of  the  nervous  elements ;  let  us  now  see  what 
use  we  may  make  of  this,  from  the  standpoint  of 
the  particular  interpretation  of  certain  phenomena  ot 
cerebral  activity. 

Let  us  take  things  as  they  normally  occur,  following 
the  natural  channels  by  which  excitations  from  the 
external  world  penetrate  into  the  organism.  Let  us 
take,  for  example,  the  impression  upon  a  sensitive  nerve 
— a  vibratory  phenomenon  which  calls  into  activity  the 
cells  of  the  retina  or  those  of  the  acoustic  nerves  ;  what 
then  takes  place  in  the  secret  recesses  of  the  nervous 
conductors  } 


PHYSIOLOGICAL   DEDUCTIONS, 


6i 


Fig.  6.  Diagram  of  the  sensor'-motor  processes  of  cerebral  activity.— i.  Opti<: 
thaiavius  with  its  centres  and  ganglionic  cells — 2.  Co>-piis  striatum— j,-  Course  of  the 
propagation  of  acoustic  impressions.  These  arrive  in  the  corresponding  centre  (4), 
are  radiated  towards  the  seusoriion  (5),  and  reflected  at  6  and  6',  to  the  large  cells  of 
the  corpus  striatum,  and  thence  at  7  and  7',  towards  the  motor  regions  of  the  spmal 
axis — S.  Course  of  sensitive  impressions.  These  are  concentrated  (at  9)  in  the  corres- 
ponding centre — radiated  thence  into  the  plexuses  of  the  sensorium  (10),  reflected  to  the 
large  cortical  cells  (11).  and  thence  propagated  to  the  large  cells  of  the  corpus  striatum, 
and  finally  to  the  different  segments  of  the  spinal  axis.— 13.  Course  of  optic  impressions. 
These  are  concentrated  I  at  14)  in  their  corresponding  centre,  then  radiated  towards  the 
sensorium  (at  15).  They  are  reflected  towards  the  large  cells  of  the  corpus  striatum  and 
afterwards  propagated  to  the  different  segments  of  the  spinal  axis  ;  18,  19',  19",  the 
antero-lateral  fibres  from  their  point  of  origin  in  the  corpus  striatum,  are  invested 
by  the  elements  of  cerebellar  innervation  which  begin  to  appear  in  the  peduncles  (19),  to 
become  considerably  thicker  at  lo',  on  a  level  with  the  region  called  the  pons  and  to 
diminish  insensibly  on  a  level  with  the  medullary  regions,  19'.— 20.  Peripheral  expansion 
of  the  olfactory  nerves. 


62  THE  BRAIN   AND   ITS   FUNCTIONS. 

Immediately  following  the  direction  of  their 
natural  channels,  these  vibrations  applied  to  each  par- 
ticular sensorial  nerve,  bring  into  play  the  specific 
activities  of  the  different  cells  of  the  centres  of  the 
optic  thalami.  (Fig.  6. — 3,  13.)  These  immediately 
take  up  the  vibration,  and  by  means  of  the  radiating 
fibres  which  unite  them  to  the  different  regions  of 
the  cortical  periphery,  transmit  to  their  sensitive 
partner-cells,  the  new  dynamic  conditions  in  which 
they  have  just  been  placed  by  the  fact  of  the  ex- 
ternal excitation. —  (See  Fig.  6. — 5  and  15.)  External 
sensorial  impressions  do  not  therefore  propagate  them- 
selves through  and  through  from  the  plexuses  of  the 
sensorial  to  those  of  the  cortical  periphery,  until  they 
have  awakened  various  intermediate  cell-territories 
which  give  them  a  new  form,  cause  them  to  undergo  a 
peculiar  metabolic  action,  and  only  launch  them  into 
the  different  plexuses  of  the  cortical  zones,  after  they 
have  animalized  them,  and  rendered  them  somehow 
more  assimilable.     (Fig.  6. — 4.  9.  14.) 

Each  special  kind  of  sensorial  excitation  is  thus 
dispersed,  and  quartered  upon  a  special  area  of  the 
periphery  of  the  brain.     (Fig.  6 — 15  and  5.) 

Anatomy  shows,  then,  that  there  are  definite  localiza- 
tions of  limited  regions,  organically  designed  to  receive, 
to  condense,  and  to  transform  such  or  such  particular 
kinds  of  sensorial  impressions. 

Experimental  physiology  has  proved  on  its  side,  that 
in  living  animals,  as  the  beautiful  experiments  of  Flou- 
rens  long  ago  showed,  it  is  possible,  by  methodically 
removing  successive  slices  of  the  cerebral  substance,  to 
cause  these  animals  reciprocally  to  lose  either  the  faculty 


PHYSIOLOGICAL  DEDUCTIONS.  63 

of  perceiving  visual,  or  that  of  perceiving  auditory 
impressions.* 

More  than  this,  Schiff,  in  his  recent  experiments,  as 
ingeniously  contrived  as  delicately  executed,  succeeded 
in  demonstrating  in  a  precise  manner,  that  in  the  animal 
under  experiment,  the  cerebral  substance  was  subject  to 
local  increase  in  temperature,  according  as  it  was  suc- 
cessively excited  by  such  or  such  kinds  of  sensorial 
impressions  ;  and  that  thus,  in  the  brain  of  a  dog,  which 
was  made  to  hear  unexpected  sounds,  such  or  such  a 
region  of  the  cortical  substance  was  heated,  and  that 
in  another,  in  which  tactile,  olfactory,  or  gustative 
sensation  was  excited,  other  regions  of  the  brain  were 
reciprocally  erethised  and  heated  in  an  isolated 
manner.-f- 

Following  up  the  process  of  the  migration  of  sensorial 
excitement  from  the  peripheral  to  the  central  regions  of 
the  system,  we  see  that  all  sensorial  impressions  arrive, 
in  the  last  stage  of  their  transit,  at  the  plexuses  of  the 
cortical  substance  ;  that  they  arrive  transformed  by  the 
action  of  the  intermediate  media  through  which  they 
have  passed  in  transitu ;  and  finally  that  they  there  die 
away  and  are  extinguished,  to  revive  under  a  new  form, 
by  bringing  into  play  the  regions  of  psychic  activity 
where  they  are  at  last  received. 

As  soon  as  the  sensorial  excitation  is  dispersed  in 
the  midst  of  the  plexuses  of  the  cerebral  cortex,  new 
phenomena  unfold  themselves. 

Here  mere  analogy  leads  us  to  think  that  the  scn- 

*  Flourens  "  Recherches  experimentales  sur  le  systeme  nerveux,"     second 
edition,  1842. 

t  Schiff,  "Archives  de  physiologic,"  1870. 


64  THE   BRAIN   AND   ITS   FUNCTIONS. 

sitive  cells  of  the  brain  may  behave  like  those  of  the 
spinal  cord,  and  that  in  the  presence  of  the  physiological 
excitations  proper  to  them,  they  will  react  in  a  similar 
fashion.  We  may,  therefore,  suppose  that  at  the  moment 
when  the  cerebral  cell  receives  the  impregnation  of  the 
external  impression,  it  becomes  erect,  as  it  were,  develops 
its  peculiar  sensibility,  and  disengages  the  specific  ener- 
gies which  it  contains. 

Thus  it  is  that  the  impression  which  is  communicated 
and  which  manifests  itself  by  a  development  of  heat  in 
certain  regions  of  the  cortex  (as  in  the  experiments  of 
Schiff ),  is  propagated  through  the  circumjacent  plexuses, 
and,  according  to  the  laws  of  undulatory  movement, 
develops  by  degrees  the  latent  activities  of  new  groups 
of  satellite  cells,  which  in  their  turn  become  new  foci 
of  activity  for  the  neighbouring  cells,  with  which  they 
are  intimately  anastomosed. 

In  this  manner  we  can  conceive  how,  in  consequence  of 
a  simple  sensorial  impression,  all  the  agglomerations  of 
nervous  elements  of  which  the  cerebral  cortex  is  com- 
posed, may  isolatedly  become  successively  engaged ; 
how  the  movement  is  communicated  from  point  to  point 
(Pig,  6 — ^.  10.  15.)  ;  how  the  individual  sensibility  of 
the  nervous  elements  begins  to  take  part  in  the 
phenomenon  ;  how  life  is  awakened  in  regions  at  first 
silent ;  and  how.  In  a  similar  manner,  the  incident 
excitation,  after  having  thrown  into  agitation  different 
zones  of  the  cortical  substance,  is  finally  transformed 
into  a  centrifugal  excitation,  reflected,  and  externally 
discharged  in  the  form  of  a  motor  act.  (Fig.  6 — 6. 
II.  16.) 

Having   followed    step   by  step,    the    phenomena  of 


PHYSIOLOGICAL  DEDUCTIONS.  6$ 

cerebral  activity  just  explained,  and  interpreted  them 
in  ordinary  language,  we  may  conclude  that  sensorial 
excitations  radiated  from  the  periphery  reach  the  regions 
of  psychic  activity,  and  that  there,  coming  under  the 
influence  of  the  elements  of  which  it  is  composed,  they 
become  transformed  into  persistent  impressions — ideas 
corresponding  to  their  origin ;  that  they  bring  into 
play  the  sensibility  and  emotivity  proper  to  these 
regions  ;  that  they  become  associated,  anastomose  one 
with  another  in  a  thousand  ways,  by  means  of  the 
organic  tissue  through  which  they  are  evolved ;  that  they 
are  amplified  and  transformed  by  the  different  zones  of 
cells  through  which  they  are  sifted  ;  and  that  finally, 
they  are  exported  and  reflected  outwards  in  the  form  of 
voluntary  motor  manifestations,  expressions  more  or  less 
indirect  of  a  primordial  phenomenon  of  sensibility. 

Now,  from  the  premisses  of  the  structure  of  the 
cortical  substance,  comprehended  as  already  indicated, 
it  may  be  possible  to  deduce  data  which  will  enable 
us  to  appreciate  the  dynamic  functions  of  the  diflerent 
zones  of  cells  contained  in  it. 

We  have  already  established,  that  the  elements  which 
compose  it  have  very  distinct  morphological  characters  ; 
that  the  zones  of  small  cells  occupy  the  sub-menin- 
geal  regions,  and  that  the  zones  of  large  cells  occupy 
the  deep  regions.  In  the  minute  constitution  of  the 
spinal  cord  we  find  similar  appearances  as  regards 
the  distribution  of  the  nervous  elements  ;  and  we 
further  know  that  the  regions  of  small  cells  are  the  seat 
of  sensitive,  those  of  large  cells  the  point  of  departure 
of  motor,  phenomena.  The  laws  of  analogy  therefore 
lead  us  to  suppose   that    morphological  imply  physio- 


66  THE  BRAIN  AND  ITS  FUNCTIONS. 

logical  analogies,  and  that  in  the  succession  of  the 
multiple  activities  of  the  cortical  substance,  we  may  pro- 
bably suppose  that  the  sub-meningeal  regions,  occupied 
by  small  cells,  are  more  particularly  the  regions  fitted 
for  the  reception  of  sensitive  impressions,  while  the 
deeper  layers,  occupied  by  the  large  cells,  appear  to  be 
more  particularly  centres  of  emission  appropriated  to 
motor  phenomena. 

This  granted,  we  arrived  at  the  following  conclusion : 
That  in  the  plexuses  of  the  cortical  substance,  there  is 
in  those  formed  by  the  small  cells  a  special  sphere  for  the 
dissemination  and  reception  of  sensitive  impressions, 
which  all  impinge  here  and  bring  into  play  the  peculiar 
sensibility  of  the  cells  ;  and  that  these  zones,  which  are 
anatomically  demonstrable,  and  which  represent  the 
posterior  sensitive  regions  of  the  spinal  cord,  receive 
in  their  essential  structure  all  the  particular  sensibilities 
of  the  organism,  and  produce  a  union  between  them. 

They  thus  form  that  matrix,  that  regio princeps  of  the 
cerebral  cortex,  which  constitutes  the  true  sensoriiLiii 
comimLue,  the  common  reservoir  into  which  all  the  im- 
pressions that  have  thrown  our  sensitive  fibres  into 
agitation,  flow,  and  in  which  they  subside.  (Fig.  i — B, 
and  Fig.  6—5,  10,  15.) 

Thus,  then,  is  constituted  this  region  which  receives 
into  its  sensitive  tissue  the  resultant  of  all  sensitive 
excitations,  from  the  external  world  as  well  as  from 
the  vegetative  life  of  the  organism,  and  which,  when 
thrown  into  agitation,  sensitized  in  its  turn,  reacts  in  a 
thousand  ways,  dispersing  in  all  directions  the  vibratory 
excitations  which  have  developed  the  energies  of  its 
elements.     It   is    its   task   gradually   to  transform  the 


PHYSIOLOGICAL  DEDUCTIONS.  6/ 

phenomena  of  sensibility,  and  finally  to  cause  sensitive 
excitations,  radiated  from  cell-plexus  to  cell-plexus,  like 
a  force  in  evolution  which  is  incessantly  transformed,  to 
produce  insensibly  a  motor  phenomenon. 

Thus  we  arrive  at  the  conclusion  that,  from  a  phy- 
siological point  of  view,  the  voluntary  motor  act  which 
emanates  from  the  brain  is  in  all  cases  nothing  more 
than  the  repercussion,  more  or  less  distant,  of  a  pri- 
mordial sensitive  impression.  (Fig.  6 — 6,  ii,  i6.) 

It  should,  however,  be  added,  that  although  the  act  of 
voluntary  motion  is,  as  a  general  rule,  only  the  indirect 
expression  of  the  agitation  of  the  sensorium,  never- 
theless, from  the  very  fact  that  it  is  evolved  throughout 
the  plexuses  of  the  cortical  substance,  laying  its 
various  zones  under  contribution,  it  is  not  a  simple, 
purely  reflex  phenomenon,  like  those  which  occur  in 
the  similar  plexuses  of  the  spinal  axis  ;  it  is  a  complex 
synthetic  phenomenon  that  resumes  in  itself  the  dif- 
ferent elements  which,  taken  together,  constitute 
human  personality.  We  may  also  say  that  if  an  act 
of  the  will  be  merely  a  phenomenon  of  transformed 
sensibility,  it  is,  nevertheless,  sensibility  doubled,  multi- 
plied by  all  the  cerebral  activities  in  agitation,  in  a 
word,  by  the  feeling  and  vibrating  human  personality, 
which  comes  into  play  in  a  somatic  form,  and  reveals 
itself  externally  by  a  series  of  rcjicctcd  and  co-ordinated 
manifestations. 


CHAPTER  VII. 

PHYSICO-CHEMICAL    PHENOMENA    OF    CEREBRAL 

ACTIVITY. 

The  nerve-cells,  considered  as  to  their  intrinsic  proper- 
ties, individually  participate  in  all  the  general  phe- 
nomena of  the  life  of  cells.  Like  all  their  fellows 
they  have  their  history,  their  genealogy,  their  periods  of 
growth  and  decay.  They  are  subject  to  alternate 
phases  of  repose  and  labour,  and,  like  them,  are  all 
gifted  with  a  specific  histological  sensibility  which  gives 
them  special  dynamic  characters. 

It  is  the  blood  alone  that  makes  them  live  and  feel ; 
it  is  it  alone  which,  as  sole  agent  of  their  incessant 
activity,  percolates  everywhere  through  the  nervous 
tissue,  and  carries  with  it  the  elements  of  all  life  and 
all  movement. 

This  is  so  true,  that  if  we  succeed  in  momentarily 
suspending  the  circulation  in  the  encephalon,  the  whole 
vital  machinery  stops  at  once,  and  every  phenomenon 
of  nervous  activity  is  at  the  same  instant  interrupted. 

Decapitated  animals  are  by  this  very  fact  deprived  of 
all  cerebral  functionment,  and,  it  is  a  very  remarkable 
fact,  that  if  we  succeed  in  artificially  restoring  to  the 
cerebral  tissue  the  nutritive  materials  of  which  it  was 
deprived  ;  if,  by  means  of  injections  of  defibrinated 
blood,  such  as  Brown-Sequard  has  experimented  with, 


PHENOMENA  OF  CEREBRAL  ACTIVITY.  69 

we  succeed  in  giving  their  habitual  stimulation  to  the 
nerve-cells,  the  signs  of  life  come  back  as  if  by  en- 
chantment, and  the  head  of  a  dog,  thus  momentarily- 
revived,  will  still  afford  ephemeral  manifestations  of  a 
conscious  perception  of  external  things  * 

In  man  the  more  or  less  complete  arrest  of  the  blood 
in  the  brain,  produces  accidents  which  are  sometimes 
overwhelming,  faintings,  and  loss  of  consciousness 
with  stupor ;  and  it  is  now  recognized,  thanks  to  the 
labours  of  modern  physiology,  that  the  greater  number 
of  those  apoplectiform  seizures,  which  were  formerly 
attributed  to  a  sanguineous  plethora  in  the  plexuses  of 
the  brain,  should  on  the  contrary  be  ascribed  to  a 
more  or  less  complete  arrest  of  the  course  of  the  blood 
in  the  capillary  plexus.  The  attacks  observed  in  these 
circumstances  may  be  legitimately  attributed  to  a  sort 
of  asphyxia  of  certain  regions  of  nerve-cells  (princi- 
pally those  of  the  sensormm,  when  we  have  to  do  with 
losses  of  consciousness,  vertigos,  and  fainting-fits) ;  the 
nervous  elements  being  stupefied  for  an  instant,  in  con- 
sequence of  the  more  or  less  complete  suspension  of 
the  arrival  of  their  nutritive  materials.t 

The  continuity  of  the  sanguine  irrigation  is,  then,  the 
sine  qua  non  of  the  regular  working  of  the  cerebral  ceils. 
It  is  at  the  expense  of  the  juices  exhaled  from  the  walls 

*  Brown-Sequard  once  injected  the  head  of  a  dog  when  separated  from 
the  trunk  with  defibrinated  and  oxygenated  blood,  and  at  the  moment  when 
the  injection  of  this  blood  had  recalled  the  manifestations  of  life,  he  called 
the  dog  by  his  name.  The  eyes  of  the  head  thus  separated  from  the  trunk 
turned  towards  him,  as  if  the  voice  of  the  master  had  still  been  heard  and 
tecognized.    (Annales  "  Medico-physiol.,"  1870,  p.  350.) 

t  Every  one  knows  that  in  fainting  fits,  and  syncope,  the  most  rapid  method  of 
bringing  them  to  an  end  is  to  place  the  patient  horizontally,  so  as  to  favour 
die  mechanical  afflux. of  blood  to  the  brain. 


yO  THE  BRAIN   AND   ITS  FUNCTIONS. 

of  the  capillaries,  that  they  feed  themselves  and  con- 
tinually repair  the  losses  sustained  by  their  integral 
constitution.* 

Plunged  into  the  midst  of  this  humid  atmosphere 
surcharged  with  phosphates,  of  which  the  materials  are 
incessantly  renewed,  they  extract  from  this  vivifying 
medium  the  elements  of  their  reconstitution  ;  like  living 
beings  plunged  into  the  terrestrial  atmosphere,  borrow- 
ing from  the  surrounding  air  the  pabidum  vitce  which 
enables  them  to  live,  and  sustains  them.  Thus  it  is  that 
they  successfully  endure  their  expenditure  of  the  phos- 
phorated element  during  the  period  of  their  diurnal 
activity,  and  that  they  can  maintain  themselves  in 
equilibrium  as  regards  their  receipts  and  expenditure. 

This  truth  was  very  clearly  brought  to  light  by  the 
ingenious  researches  of  Byasson,  who  has  pertinently 
shown  that  every  cerebral  cell  in  functioning  expends  its 
phosphorized  materials,  and  that  this  waste  resulting 
from  cerebral  activity,  like  the  natural  physiological 
excretions,  is  drained  away  from  the  organism  by 
passing  out  in  the  urine,  in  the  form  of  sulphates  and 
phosphates,  which  serve  as  a  chemical  measure  of 
the  intensity  of  cerebral  work  done  in  a  given  time.f 

*  The  blood  which  comes  to  the  brain  red  and  oxygenated,  returns  by  the 
capillaries  black  and  charged  with  carbonic  acid.  (Gavarret,  "  Phenomenes 
physiques  de  la  vie."    Annales  medico- psychol.  1870,  p.  347.) 

t  To  arrive  at  these  results,  Byasson  for  several  days  submitted  to  a  special 
physical  and  moral  regimen.  He  estimated  exactly  the  quantity  of  phosphates 
and  sulphates  which  entered  into  his  diet,  and  also  the  quantity  excreted.  At 
the  end  of  a  certain  time,  these  fundamental  data  having  been  ascertained,  he 
began  to  work  his  brain,  and  in  proportion  to  the  amount  of  his  work,  the 
diet  remaining  constant,  the  quantity  of  sulphates  and  phosphates  excreted 
by  the  urine  had  increased  in  a  notable  manner.  (Byasson,  "  Essai  sur  la 
relation  qui  existe  a.  I'etat  physiologique  entre  I'activite  cerebral  et  la  composi- 
tion des  urines."    Journ.  danat.,  de  Robin,  1869,  p.  560.) 


PHENOMENA  OF   CEREBRAL  ACTIVITY.  7 1 

These  facts  show,  then,  the  enormous  influence  which 
the  blood  exercises  upon  the  vegetative  phenomena  of 
the  Hfe  of  the  nerve-cells,  and  to  what  an  extent  their 
individual  dynamic  activity,  and  consequently  the  life 
of  the  whole  system,  depends  upon  it. 

It  is  the  blood  that  carries  everywhere  with  its  un- 
interrupted currents  the  vivifying  stimulation  which 
causes  the  cells  to  feel,  to  become  erect,  and  to  associate 
for  co-ordinated  actions.  In  the  purely  sensitive  regions, 
where  the  phenomena  of  conscious  personality  are  inces- 
santly in  process  of  evolution,  it  keeps  them  constantly 
awake,  and  thus  sustains  in  us  the  conscious  idea  which 
we  possess  of  the  external  world.  In  the  motor  regions  it 
enables  the  nervous  elements  to  accumulate,  as  in  con- 
densers, a  store  of  nervous  influence  destined  to  pass 
into  the  dynamic  condition  as  soon  as  a  call  is  made 
upon  them.  It  is  everywhere  present,  flowing  every- 
where, and  evoking  the  specific  innervation  of  each  of 
the  cell-territories  which  it  animates  and  bedews,  thus 
enabling  them  to  renew  their  latent  energies. 

When  once  provided  with  the  necessary  elements  of 
nutrition,  the  cerebral  cell  becomes  capable  of  entering 
into  action,  and  performing  the  dynamic  function  for 
which  it  is  designed.  This  new  phase  under  which  it 
reveals  itself  is  characterized  : — 

1.  By  an  acceleration  of  the  blood-currents  in  the 
functioning  regions. 

2.  By  a  local  development  of  heat  in  these  regions. 

I. — If  it  be  incontestably  demonstrated  what  an  itji- 
portant  influence  the  regularity  of  circulatory  pheno- 
mena has  in  evoking  the  activity  of  nerve-cells,  it  is  on 
the  other  hand  very  curious  to  note  what  an  influence 


^2  THE  BRAIN   AND   ITS   FUNCTIONS. 

the  activity  of  these  same  cells  may  have  in  return  on 
the  vascular  irrigation  designed  to  provide  for  their 
nutrition  as  well  as  their  expenditure. 

It  is  not,  indeed,  without  a  certain  astonishment  that 
we  observe  that  if,  on  the  one  hand,  the  nerve-cells  play 
a  passive  part  with  regard  to  the  circulation  which  feeds 
them — if  they  are  in  subjection  to  it,  and  are  veritably 
its  tributaries ;  by  an  inverse  phenomenon,  from  the 
moment  they  become  active  their  position  changes,  and, 
ceasing  to  be  subject  as  they  were,  they  in  turn  become 
dominant.  From  the  very  fact  that  they  are  working — 
that  there  in  certain  isolated  spaces  they  develop  a 
state  of  nervous  erethism — they  at  the  same  time  deter- 
mine hie  et  nunc  a  concomitant  influx — they  make  an 
appeal  to  the  blood,  and  even  turn  to  their  own  profit 
the  irrigation  of  certain  neighbouring  regions.* 

Thus  the  brain,  as  regards  the  phenomena  of  circu- 
lation, is  at  the  same  time  active  and  passive  ;  it  is 
of  necessity  subject  to  their  influence,  and  cannot,  on 
pain  of  cessation  from  all  work,  refuse  their  aid  ;  and 
yet,  at  a  given  moment,  it  reacts,  solicits  them,  makes 
appeals  to  them,  and  thus  unconsciously  directs  the  vaso- 
motor actions  designed  to  maintain  the  integrity  of  its 
vital  energy. 

Thus  from  this  double  influence  of  the  phenomena 
of  the  circulation  on  those  of  cerebral  activity,  and 
those  of   cerebral  activity  on  the  acceleration  of  the 

*  We  may  perhaps  attribute  to  an  accidental  derivation  of  blood  towards  a 
circumscribed  portion  of  the  brain  that  is  in  a  state  of  erethism,  and  the  con- 
sequent draining  of  the  circumjacent  regions,  certain  phenomena  of  cerebral 
lite  in  which,  under  the  impress  of  a  strong  preoccupation,  a  concentration  ol 
the  mind  upon  a  single  point,  we  momentarily  lose  the  notion  of  the  surround- 
ing mediuiu,  aud  cease  to  perceive  what  is  passing  around  us. 


phetnOmena  of  cerebral  activity.  73 

flow  of  blood,  a  vicious  physiological  circle  results, 
calculated  to  have  an  inevitable  influence  upon  the 
infinite  series  of  regular  cerebral  operations,  as  well  as 
upon  the  progressive  evolution  of  pathological  pheno- 
mena, which  mostly  are  but  exaggerations  of  the 
normal  actions  of  the  organism. 

Every  one  knows  how  fatal  chronic  lesions  of  the 
capillary  plexuses  are  to  the  delicate  substance  of  the 
cerebral  cells — how  the  plastic  exudations  which  pro- 
ceed from  the  vessels,  the  fibro-albuminous  deposits 
which  become  infiltrated  into  the  tissue  and  interstices 
of  the  cells,  become  like  so  many  foreign  bodies  hostile 
to  life,  and  injurious  to  the  physiological  medium  whence 
they  draw  the  elements  of  their  normal  constitution. 

Every  one  knows,  further,  how  moral  causes — too 
energetic  work,  which  exceeds  the  amount  of  the 
reserved  nerve-force  —  prolonged  vigils,  which  do 
not  permit  the  recuperation  of  lost  materials — pre- 
occupations concerning  a  single  subject,  which  induce  a 
condition  of  chronic  congestion  within  certain  circum- 
scribed limits — are  so  many  morbid  modes  of  excite- 
ment which  maintain  a  permanent  condition  of  local 
erethism,  and  thus  indirectly  become  the  causes  of 
those  repeated  affluxes  of  blood  which  are  so  inevitably 
followed  by  exudations  of  all  kinds  and  persistent  new- 
formations  (the  lesions  of  general  paralysis). 

Hence  that  preponderant  influence  which  the  whole 
series  of  moral  afl*ections  exercises  upon  the  genesis 
of  mental  maladies.  Whether  they  be  derived  from 
an  intellectual  excitement  prolonged  beyond  physio- 
logical limits,  or  result  from  profound  disturbances 
occurring  in  the  emotional  sphere  of  the  sensorium,  in 
7 


74  THE  BRAIN  AND   ITS   FUNCTIONS. 

consequence  of  trouble,  disappointment,  misfortunes 
of  all  kinds,  the  minute  mechanism  of  their  advent  is 
always  fundamentally  the  same.  It  is  by  the  physio- 
logical channel  they  introduce  themselves  into  the 
organism  ;  it  is  under  the  form  of  regular  excitations — 
shocks  propagated  along  the  normal  processes  of  cere- 
bral life — that  they  implant,  develop,  and  perpetuate 
themselves ;  and  the  incurable  disorders  they  leave 
behind  them  are  but  the  indirect  effects  of  disturbances 
of  nutrition  in  the  nervous  plexuses,  proceeding  from 
this  single  source,  the  afflux  of  blood  too  frequently 
provoked.* 

Sleep. — By  an  inverse  phenomenon,  if  the  cerebral  cell, 
from  the  very  fact  that  it  is  in  its  period  of  erethism,  its 
working  period,  becomes  the  occasion  of  a  call  upon  the 
blood  destined  for  its  activity,  this  curious  fact  occurs, 
that  so  soon  as  this  activity  begins  to  slacken,  so  soon 
as  fatigue  announces  itself,  and  its  histological  sensibility 
is  exhausted  by  the  action  of  external  impressions,  the 
vascular  irrigation  is  modified  simultaneously.  It  fol- 
lows step  by  step  the  decreasing  phase  of  the  dynamic 
activity  of  the  cells  that  depend  upon  it,  and  at  the 
same  time  that  the  brain  becomes  weary,  and  that  the 
sum  of  its  functional  energies  diminishes,  the  mass  of 
blood  which  flows  to  it  becomes  less,   the   capillaries 


*  Calmeil  thus  expressed  the  same  thougJit.  "All  the  so  called  moral 
influences,  whether  they  betray  themselves  by  the  persistence  of  annoyances  or 
rei^rets,  or  take  the  forms  of  jealousy,  hatred,  or  ambitious  disappointments,  may 
concur  to  produce  a  morbid  accumulation  of  blood  in  the  encephaUc  capillaries, 
^Calmeil,  "  Maladies  inflammatoires  du  cerveau,"  vol.  i,  p.  5.) 

See  also  Forbes  Winslow,  on  softening  of  the  brain  occurring  from  anxiety 
and  forced  exercise  of  the  organ,  and  consisting  in  feebleness  of  mind 
(••  Annales  naedico-psychol,"  1850,  vol.  ii.  p.  711.) 


PHENOMENA   OF   CEREBRAL  ACTIVITY.  75 

are  less  gorged  with  blood,  and  the  cerebral  tissue 
insensibly  becomes  exsanguine. 

This  is  that  new  state  of  cerebral  ischsemia,  opposed 
to  the  phase  of  congestive  activity,  which  as  an  alter- 
native fact  of  the  general  order  that  exists  in  the  brain 
of  all  living  beings,  inevitably  reveals  itself  whenever 
their  cerebral  cells,  having  exhausted  their  accumulated 
nervous  forces,  become  fatigued  by  exercise  and  fall 
into  the  physiological  collapse  of  sleep.* 

Where  the  life  of  the  nervous  elements  is  stilled,  a 
stillness  also  takes  place  in  the  most  minute  currents 
of  the  circulation,  and  these  two  phenomena,  which  act 
and  react  on  one  another  in  the  ascending  phases  of 
activity,  similarly  affect  each  other  in  its  descending 
phases.  When  the  vital  movement  becomes  slack,  and 
histological  sensibility  dull,  the  demand  upon  the  blood 
is  less  imperious. 

2. — If,  from  a  chemical  point  of  view,  the  phenomena 
of  cerebral  activity  are  characterized  and  gauged  in  a 
precise  manner  by  the  real  loss  of  brain-substance,  and 
the    passage    of    a    certain    quantity  of    phosphorized 

*  The  condition  of  comparative  anaemia  in  the  brain  during  sleep  has  been 
directly  proved  by  different  observers;  thus  Ca'dweil,  in  the  case  of  a  wound 
in  the  head,  with  loss  of  substance  in  the  bones  of  the  cranium,  observed  that 
when  the  patient  was  plunged  in  deep  and  peaceful  sleep,  the  brain  remained 
almost  immovable  in  its  envelope,  but  that  when  he  was  dreaming  it  increased 
in  volume,  and  when  the  dream  was  vivid  it  protruded  through  the  opening. 
Blumenbach  in  an  analogous  case,  similarly  remarked  that  the  brain  sub- 
sided during  sleep  and  that  waking  was  accompanied  by  a  more  or  less  con- 
siderable afflux  of  blood,  and  an  augmentation  of  volume.  ("Archives 
generales  de  Medicine,"  vol.  i.  637.)  Durham  also  has  instituted  direct 
e  periments  to  prove  that  during  sleep  the  brain  becomes  anaemic.  ("Guy's 
Hospital  Reports,"  i860,  vol.  vi.  p.  149.)  See  confirmatory  experiments  by 
Claude  Bernard.  "  Lecons  sur  les  anesthetiques,"  p.  X17.  Paris,  J.  B. 
BaiUere,  1875. 


j6  THE  BRAIN  AND   ITS   FUNCTIONS. 

matters  in  the  urine,  from  a  physical  point  of  view  they 
present  characters  which  are  no  less  significant,  and  no 
less  important  to  recognize. 

The  authors  who  have  already  occupied  themselves 
with  the  question,  as  to  what  appreciable  physical 
modifications  are  presented  by  the  brain-substance 
while  in  activity,  have  noted  in  a  precise  manner  that 
this  inward  labour  reveals  itself  by  sensible  signs,  in  the 
form  of  a  more  intense  disengagement  of  heat ;  and  that 
the  brain,  like  a  muscle  in  action,  manifests  its  dynamic 
power  by  a  local  increase  of  heat,  appreciable  by  the 
instruments  of  the  physical  laboratory. 

Thus,  Lombard  (of  Boston),  who  was  the  first  to 
institute  experiments  in  this  direction,  arrived  at  the 
following  results,  by  means  of  very  exact  thermo-electric 
apparatuses : — 

"  In  the  condition  of  cerebral  repose,"  he  says,  "  during 
wakefulness,  the  temperature  of  the  head  varies  very 
rapidly.  The  variations  are  very  slight,  not  attaining 
Y-^gth  of  a  degree  centigrade,  but  they  are  not  the  less 
worthy  of  attention,  for  this  reason — that  they  are 
confined  to  the  head. 

"The  variations  of  temperature  appear  to  be  con- 
nected with  different  degrees  of  cerebral  activity. 
During  active  brain-work  it  never  exceeds  -J^th  of  a 
degree  centigrade. 

"  Every  cause  that  attracts  the  attention — a  noise,  or 
the  sight  of  an  object  or  a  person — produces  elevation 
of  temperature. 

*'  An  elevation  of  temperature  also  occurs  under  the 
influence  of  an  emotion,  or  during  an  interesting  reading 
aloud. 


PHENOMENA  OF  CEREBRAL  ACTIVITY.  J*] 

"  This  elevation  of  temperature  is  especially  well- 
marked  in  the  region  of  the  occiput." 

These  experiments,  as  we  see,  apply  only  to  the 
appreciation  of  temperature  externally  estimated,  on 
the  skin  of  the  cranium.  The  brain  was  not  directly 
investigated. 

Schiff  has  supplied  this  omission,  he  has  entered  the 
cranium,  and  by  means  of  thermoscopic  instruments  of 
extreme  sensibility  has  succeeded  in  directly  exam- 
ining the  cerebral  substance  at  the  moment  when  it 
came  in  contact  with  external  excitations,  and  thus 
determining  what  degree  of  elevation  of  temperature 
the  brain  is  susceptible  of  attaining  in  its  operations. 

This  ingenious  physiologist  has  therefore  succeeded  in 
defining  not  only  what  regions  of  the  cerebral  cortex  are 
isolatedly  called  into  play  by  such  or  such  kinds  of 
sensorial  impressions,  and  demonstrating  experimentally 
that  there  are  isolated  circumscribed  spots  reserved  for 
such  or  such  kinds  of  sensorial  impressions  (as  has 
already  been  described  on  the  authority  of  anatomy)  ; 
but  also  that  the  arrival  of  these  impressions  resolves 
itself  into  a  local  development  of  heat  in  the  special  area 
where  it  disseminates  itself ;  and  that  the  heat  thus 
developed  is  a  dynamic  phenomenon  independent  of 
the  circulatory  activity,  a  true  vital  reaction  of  the 
sensorium — that,  in  a  word,  it  is  the  direct  result  of 
the  participation  of  the  psychic  element  on  the  arrival  of 
the  sensorial  excitation. 

"  Thus,"  he  says,  "  the  psychical  activity,  independently 
of  the  sensorial  impressions  which  call  it  into  play,  is  con- 
nected with  a  production  of  heat  in  the  nervous  centres, 
a  greater  amount  of  heat  than  that  which  simple  sen- 


yS  THE   BRAIN   AND   ITS   FUNCTIONS. 

sorial  impressions  engender.  This  conclusion  is  justified 
by  the  decrease  of  the  calorific  effect  of  a  strong  and 
always  identical  sensorial  impression,  which  animals 
have  been  made  to  experience  many  times  in  succession. 
Let  us  take  a  pullet,"  he  adds,  "whose  sight  or  hearing 
we  assail  by  appropriate  means.  The  first  impression 
which  the  unprepared  animal  receives  will  excite  in  it 
more  intense  psychical  reflex  actions  than  the  succeed- 
ing excitations  of  the  same  nature,  since  it  insensibly 
becomes  habituated  to  them."  Thus,  by  eliminating 
gradually  the  part  played  by  psychical  action  in  sen- 
sorial absorption,  he  arrives  at  an  estimate  of  the  heat 
evoked  by  the  arrival  of  simple  sensorial  impres§ions, 
and  that  which  proceeds  from  the  direct  participation 
of  the  psychical  activity  at  the  beginning  of  the  experi- 
ment.* 

We  thus  understand,  after  this  series  of  experiments, 
how  prolonged  efforts  of  the  mind,  and  moral  emotions 
of  all  sorts,  from  the  very  fact  of  their  awaking  the 
activity  of  the  sensorm7n,  are  calculated  to  have  an 
immediate  effect  upon  the  essential  phenomena  of  the 
nutrition  of  the  brain. 

They  show  us,  indeed,  on  the  one  hand,  that  sustained 
intellectual  work  is  accompanied  by  a  loss  of  phos- 
phorized  substance  on  the  part  of  the  cerebral  cell  in 
vibration  ;  that  it  uses  it  up  like  an  ignited  pile  which  is 
burning  away  its  own  essential  constituents  j*!"  and  that, 

*  Schiff,  I.e.,  "  Archives  de  Physiologie,"  1870,  p.  451. 

t  Louyer-Villermay  cites  the  example  of  a  celebrated  lawyer  who  lost  hiji 
memory  in  consequence  of  too  long-continued  intellectual  work;  and  Moreau  de 
la  Sarthe  reports  a  similar  case  which  occurred  in  a  German  savant,  after  an  in- 
tense concentration  of  mind.  We  also  know  of  a  great  number  of  musicians 
wtio  have  become  deaf  by  the  immoderate  exercise  of  the  organ  of  hearing. 
"Joitrnal  d'hygifene,"  1875.     (De  la  surdite  chez  les  Musiciens,  par  Dr.  Piat.) 


PHENOMENA  OF   CEREBRAL  ACTIVITY.  79 

on  the  other  hand,  all  moral  emotion  perceived  through 
the  sensorium^  all  effective  participation  of  this  same 
saisorium  in  an  excitation  from  the  external  world, 
becomes  at  the  same  time  the  occasion  of  a  local  develop- 
ment of  heat. 

These  facts  are  destined  to  have  a  direct  effect  upon 
our  knowledge  of  the  essential  conditions  of  the  in- 
tegrity of  the  cerebral  functions,  and  to  formulate 
absolute  hygienic  principles  with  regard  to  them. 

It  stands  to  reason,  indeed,  that  if  the  cerebral  cell 
expend  its  reserve  material  during  its  diurnal  activity, 
it  is  absolutely  necessary,  to  enable  it  to  continue  alive 
and  in  health,  that  it  shall  repose  and  sleep  regularly. 
Sleep  is  to  the  brain,  what  needful  repose  is  to  our 
fatigued  limbs,  the  necessary  condition  of  its  health. 
Every  one  knows,  indeed,  how  great  is  the  number  of 
individuals  who  have  sown  the  seeds  of  a  cerebral 
disease  by  a  prolonged  infraction  of  these  simple  laws  of 
hygiene,  and  who  through  reiterated  vigils  and  exag- 
gerated expenditures  of  activity,  have  thus  passed  the 
physiological  limit  of  the  resources  at  their  disposal,  and 
incurred  expenditure  above  their  receipts. 

On  the  other  hand  this  development  of  heat,  which  is 
produced  in  certain  circumscribed  localities  of  the  brain 
when  an  emotion  or  sensorial  impression  is  reverberating 
through  the  plexuses  of  the  sensorhnn,  further  shows  us 
with  what  circumspection  we  should  manage  this  kind 
of  excitation  in  individuals  whose  brain  is  in  a  painful 
condition,  either  from  a  recent  congestion,  or  from  for- 
mer congestions  grafted  one  upon  another. 

We  all  know  from  more  or  less  personal  experience, 
that  when  we  have  a  headache,  and  our  sensoriuui  is 


8o  THE   BRAIN   AND  ITS   FUNCTIONS. 

in  a  state  of  hyperaesthesia,  the  smallest  noises,  the 
sb"ghtest  external  incidents,  produce  in  us  painful  shocks, 
and  that  the  absolute  incapacity  for  work  is  most 
painful. 

All  doctors  know  how  often,  in  persons  excited  by 
the  occurrence  of  repeated  cerebral  congestions,  paraly- 
tics, maniacs,  and  even  patients  wiin  certain  forms  of 
melancholia,  the  unexpected  calling  up  of  an  old  emo- 
tion, the  sight  of  a  relative,  may  have  a  sad  effect  upon 
their  cerebral  condition.  We  see,  indeed,  their  faces 
redden  and  grow  pale,  and  very  often  the  effect  of  an 
emotion  inopportunely  provoked,  is  but  the  prelude  to 
the  return  of  more  and  more  serious  congestive  acci- 
dents. 


PART  II, 


GENERAL     PROPERTIES    OF    THE    NERVOUS 

ELEMENTS. 


The  phenomena  of  the  life  of  the  nervous  centres, 
spite  of  their  apparent  complexity,  are  nevertheless 
regulated  by  laws  which  are  in  general  simple — 
common  principles,  which  indisputably  give  them  an  air 
of  near  relationship.  These  common  principles  are, 
moreover,  themselves  reducible  to  elementary  vital  pro- 
perties, which  form  the  basis  of  each  of  them  in  par- 
ticular, and  constitute,  in  a  manner,  the  simple  prim- 
ordial principles  which  we  constantly  find  underlying 
every  combination  of  nervous  activity,  however  com- 
plicated it  may  be.  These  fundamental  properties, 
which  thus  serve  as  elementary  materials  for  every 
dynamic  action  of  the  system,  may  at  the  present  day 
be  thus  epitomized,  under  three  principal  heads  : — 

1.  Sensibility^  by  which  the  nerve-cells  feel  excitation 
from  without,  and  react  in  consequence,  by  virtue  of 
the  excitement  of  their  natural  affinities. 

2.  Organic  PJiosphorescence,  by  which  the  nervous 
elements,  like  bodies  which  have  received  the  vibrations 
of  light,  preserve  for  a  prolonged  period  traces   of  the 


82  THE   BRAIN   AND   ITS  FUNCTIONS. 

excitations  which  have  in  the  first  place  set  them  in 
action,  thus  storing  up  within  themselves  phosphorescent 
traces,  which  are  records  of  the  received  impressions. 

3.  AutoinatisiUy  which  expresses  the  spontaneous 
reactions  of  the  living  cell,  which  sets  itself  in  motion 
of  its  own  accord  {inotit  propria),  and  in  an  unconscious 
and  automatic  manner  expresses  the  different  states 
of  its  sensibility  thrown  into  agitation. 

It  is  the  history  of  these  various  general  properties  of 
the  nervous  elements  that  we  are  now  about  to  study  in 
due  course,  in  the  physiological  part  of  this  work.  These 
properties  once  defined  and  known,  we  shall  attack  the 
study  of  the  different  combinations  to  which  they  adapt 
themselves  by  combining  one  with  another  ;  and  thus, 
proceeding  from  the  known  to  the  unknown,  from  the 
simple  to  the  composite,  we  shall  advance  with  better 
ascertained  points  of  support  into  that  domain,  so  com- 
plex, and  at  the  same  time  so  rich  in  interesting  pros- 
pects— that  of  cerebral  activity  proper. 


BOOK    I. 

SENSIBILITY   OF   THE    NERVOUS   ELEMENTS. 


CHAPTER   I. 

GRADUATION  AND  GENEALOGY  OF  THE  PHENOMENA 

OF   SENSIBILITY. 

Sensibility  is  that  fundamental  property  which 
characterizes  the  Hfe  of  cells.  It  is  by  means  of  it 
that  the  living  cells  come  into  contact  with  the  medium 
that  surrounds  them,  and  that  they  react  motii  propria, 
by  virtue  of  their  natural  affinities  which  are  thrown 
into  agitation,  and  exhibit  a  desire  for  the  excitations 
which  gratify  them,  and  a  repulsion  for  those  that  are 
unpleasant  to  them.  Attraction  for  agreeable  and  re- 
pulsion for  disagreeable  things  are  the  indispensable 
corollaries  of  every  organism  fitted  for  life,  and  appa- 
rently the  elementary  manifestation  of  all  sensibility. 

Sensibility,  which  is,  perhaps,  itself,  in  the  organic 
world,  only  the  transformation  of  those  blind  forces, 
which  attract  among  themselves  the  crystalline  mole- 
cules of  the  inorganic  world,  and  group  them  according 
to  their  proper  affinities  ;  this  phenomenon,  sensibility, 


84  THE  BRAIN   AND   ITS   FUNCTIONS. 

begins  to  appear,  in  its  most  simple  forms,  with  the  first 
rudiments  of  life. 

It  is  in  the  unicellular  organisms  of  the  vegetable 
kingdom  that  it  first  embodies  itself  and  reveals  itself 
in  its  own  shape  ;  and  here  it  shows  itself  as  a  property 
of  tissue,  very  distinctly  connected  with  the  very  sub- 
stance of  the  amorphous  protoplasm  of  which  it  is  the 
endowment,  under  the  form  of  vague  diffuse  contractility, 
no  special  element  being  reserved  for  it,  and  no  nerve- 
cells  being  as  yet  extant* 

Little  by  little,  as  the  living  cells  group  together  and 
form  more  dense  agglomerations,  the  phenomena  of  sen- 
sibility become  more  distinctly  evident,  and  soon^we 
find  them  provided  with  special  apparatuses  designed 
to  serve  them  as  a  support,  and  to  condense  and  perfect 
their  modes  of  activity  ;  while  in  the  superior  animals 
they  become  more  and  more  highly  endowed,  to  arrive 
at  man  as  the  last  term  of  their  long  evolution,  and 
produce  those  phenomena  so  rich,  so  varied,  so  delicate, 
defined  in  conci-eto  under  the  name  of  the  moral  sense. 

In  this  chapter  we  shall  follow  the  process  of  the 
evolution  of  sensibility,  from  the  most  elementary 
phases  under  which  it  shows  itself  at  its  point  of  origin, 
to  the  moment  of  its  most  complete  expansion  in  man. 

Sensibility,  we  may  say,  in  its  most  simple  revelations 
in  unicellular  organisms,  at  first  appears  in  a  vague 
and  undetermined  form.  It  reveals  itself  by  that 
essential  tendency  which  these  protorganisms  have,  to 
seize  upon  substances  which  gratify  their  natural  affini- 

*  Naturalists  have  made  known  to  us  beings  of  an  organization  so  simple 
that  their  entire  body  is  formed  of  but  one  cell.  Their  whole  development, 
their  whole  existence,  is  shut  up  within  limits  thus  strict.  We  may  mention 
theg7'e£ar/nes  in  particular.     (Frey,  "  Histologic  et  Histoc.hemie,"  p.  74.) 


THE   PHENOMENA   OF  SENSIBILITY.  85 

ties  and  avoid  such  as  are  inimical  to  them.  It  regu- 
lates and  governs  the  continuity  of  the  purely  trophic 
phenomena  of  the  life  of  cells.* 

In  vegetables  the  phenomena  of  sensibility  have 
already  taken  more  distinctly  marked  forms.  Their 
cycle  is  no  longer  restricted  to  the  local  operations  of 
rough  and  ready  assimilation  and  disassimilation. 

Vegetable  cells,  even  when  agglomerated  in  but 
small  groups,  have  become  sensitive  and  impressionable 
by  external  agents.  Calorific  and  luminous  impres- 
sions produce  a  certain  effect  upon  them,  and  if  this 
effect  be  grateful  to  certain  natural  affinities,  we  may  see 
them  gradually  inclining  in  the  direction  from  whence 
these  excitations  come.  They  turn  automatically  towards 
the  sun,  awake  with  him  when  he  appears,  sleep  when 
he  has  disappeared,  and,  in  a  word,  present  that  series 
of  unconscious  and  graduated  movements  by  virtue  of 
which  they  tend  towards  the  realization  of  their  latent 
satisfactions.f 

Botanists  have  already  described  those  curious  phe- 
nomena of  vegetable  sensibility  by  virtue  of  which  we 
see  the  petals  of  certain  flowers  fold  up  at  night  and 
unfold  in  the  day  time ;  the  stamens  of  the  barberry, 


*  The  gregarines,  which  are  met  with  in  troops  as  living-  parasites  in  the 
alimentary  canal  of  insects  and  other  animals,  are  not  only  destitute  of  a 
mouth,  but  even  of  vibratile  cilia.  They  are  simple  cells  with  apparent  nuclei. 
(Hartmann,  "Conscience  des  plantes."  "Revue  Scientifique,"  July  1S73, 
p.  623.) 

f  Plants  which  catch  insects  are  sensitive  to  the  touch ;  climbing  plants 
discern  points  of  support.  Tlie  leaf  of  the  vine  feels  the  hght,  towards  which  it 
strives  to  turn  the  right  side,  and  every  flower  feels  it,  and  strives  to  bend 
its  head  towards  it.  The  mimosa  feels  and  reacts.  It  is  the  essence  of 
every  motion  that  it  shall  be  preceded  by  sensibility.  (Hartmann,  loc.  at,, 
p.  625.) 


86  THE  BRAIN   AND   ITS  FUNCTIONS. 

under  the  excitement  of  a  light  touch  apply  themselves 
to  the  pistil  ;  the  flowers  of  the  water-lily  hide  them- 
selves at  the  bottom  of  the  water  while  they  wait  for 
the  day.  It  is  even  more  astonishing  to  see  what  hap- 
pens with  sensitive  plants,  and  to  observe  how  that 
curious  vegetable,  mimosa  pudica,  presents  in  itself  all 
the  most  delicate  manifestations  of  the  impressionabiUty 
of  living  beings.* 

Like  an  animal,  it  feels  and  reacts  on  the  contact  of 
the  lightest  touch  ;  feels  inequalities  of  temperature  ;-|- 
is  influenced  and  struck  with  anaesthesia  by  the  in- 
halation of  chloroform  ;  like  an  animal,  moreover,  its 
sensitive  unity  forms  a  complete  whole  ;  its  leaflets  and 
rootlets  are  united  in  such  an  intimate  conseitstts  that 
if  its  rootlets  be  subjected  to  the  action  of  any  irritant, 
its  leaflets  are  affected  at  the  same  time,  and  sympathize 
painfully  with  their  sister  cells  of  the  lower  regions  which 
have  been  thrown  into  agitation  ;  just  as  we  see  that 
sensibility  when  developed  in  any  region  of  an  animal 
whatever,  has  a  generalized  reaction  all  over  the 
organism. 

*  Marked  movements  are  performed  every  evening  by  vegetables  with 
composite  leaves,  like  the  cytisus  or  robinia  pseud-acacia.  We  see  these  plants 
make  their  preparations  for  night  every  evening — some  simply  fold  their  leaves, 
others,  with  more  foresight,  prudently  enclose  their  flowers.  The  great  lotuses 
of  the  Nile,  and  the  water-lilies  of  our  own  lakes,  draw  down  their  carefully 
closed  corollas  to  the  bottom  of  tlieir  waters ;  and  the  sun  must  have  come 
next  day  to  illumine  the  earth  before  the  chilly  and  sleeping  plant  consents  to 
open  its  petals. 

The  sleep  of  plants  is  related  to  the  greater  or  lesser  intensity  of  the  light 

with  which  they  are  surrounded;   and,  what  is  more  conclusive,  plants  which 

have  been  strongly  illuminated  at  night,  while  they  are  in  obscurity  during  the 

day,  have  changed  their  habits  so  as  to  sleep  in  the  day  and  wake  at  night. 

Edmond  Grimard,  "  De  la  sensibilite  veg^tale."     "  Revue  w'es  Deux  Mondes," 

868,  p.  379.) 

t  Griipard,  loc.  cit.,  p.  385. 


THE   PHENOMENA  OF   SENSIBILITY.  ^J 

In  the  animal  kingdom  sensibility  reveals  itself  in  its 
origin  by  phenomena  exactly  comparable  with  those 
which  we  have  just  sketched. 

There',  in  the  form  of  amoeboid  movements  of  the 
white  corpuscles  and  ciliated  cells,  and  contractility 
of  the  protoplasmic  cells,*  it  shows  itself  to  us  under 
the  appearance  of  purely  histological  sensibility,  and 
not  as  yet  in  the  shape  of  sensibility  belonging  to  a 
living  autonomous  individuality. 

In  the  protozoa,  rhizopods,  and  certain  polyps,  it 
becomes  more  and  more  distinct,  and  by  the  very 
complex  operations  through  which  it  manifests  itself, 
we  perceive  how  well  these  protorganisms  of  the 
animal  kingdom  are  provided  with  active  and  vital 
energy,  and  how  distinctly  general  sensibility  is  inherent 
in  them  and  combined  with  their  substance. 

In  these  elementary  forms  of  animal  life,  the  phe- 
nomena of  sensibility  are  first  united  with  an  organized 
tissue.  They  are  divided  among  as  many  cells  as  the 
individual  contains ;  and  they  exist  in  a  vague  and 
diffuse  manner,  without  there  being  as  yet  a  special 
system  of  anatomical  elements,  designed  to  serve  them 
as  an  appropriate  receptacle. 

Soon,  as  we  ascend  in  the  series  of  beings,  new  factors 
are  added  to  the  preceding  ;  the  phenomena  become 
complicated  as  they  grow  more  perfect,  and  we  then  see 
that  in  proportion  as  animal  organisms  develop  them- 
selves, and  their  agglomerations  of  cells  become  more 
numerous,  there  takes  place  among  them,  as  it  were,  a 
natural  selection  of  the  physiological  work  to  be  per- 
formed.     Some  are  gifted   with  such  or  such  specifi^c 

*  Wund,  "  Physioloi^ie,"  p.  83. 


S8  THE  BRAIN   AND   ITS   FUNCTIONS. 

aptitudes,  and  appropriate  such  or  such  a  function,  while 
others,  gifted  with  such  or  such  a  different  aptitude, 
reserve  themselves  for  such  or  such  another.  For  its 
better  performance  there  is  a  division  of  labour. 

This  natural  division  of  the  living  forces  of  the  living 
individual,  which  are  thus  distributed  among  the  different 
departments  of  its  substance,  constitutes  the  first  outline 
of  the  nervous  system. 

It  soon  appears,  like  an  organ  of  perfectionment  im- 
planted in  the  organism.  It  is  henceforward  the  grand 
dispenser  of  sensibility  in  general,  and  is  designed  to 
collect,  to  drain  all  the  scattered  forms  of  sensibility, 
to  regulate  their  course,  to  condense  them  in  its  own 
reservoirs,  to  purify  them  by  the  participation  of  its 
substance,  to  make  them  leap  forth  in  the  form  of  motor 
excitations,  or  to  transform  them,  like  the  perfected 
products  of  its  own  industry,  into  subtle  and  quintes- 
sential materials,  destined  to  co-operate  in  the  most 
subtle  phenomena  of  psycho-intellectual  life. 

Humble  in  its  origin,  the  nervous  system,  as  F.  Leydig 
has  pointed  out,  makes  its  first  appearance  in  the  midst 
of  the  living  tissues  in  the  form  of  three  or  four  cells, 
independent  one  of  another.*  One  step  further,  and 
the  cells  are  united  within  a  common  envelope,  a  first 
nervous  ganglion  being  thus  constituted.  Little  by 
little  the  work  of  evolution  completes  itself;  ganglion 
is  united  to  ganglion  ;  these  soon  dispose  themselves  in 
the  form  of  two  lateral  rows,  which  emit,  right  and  left, 
radicles  which  plunge  into  the  surrounding  tissues,  and 
soon  these  two  lateral  chains,  approaching,  become 
fused  together,  and    thus    constitute    a   central    unity, 

*  Claude  Bernard,  "Systeme  nerveux,"'  vol.  i.  p.  506. 


THE   PPIENOMENA   OF   SENSIBILITY.  89 

or  axis,  around  which  all  the  nervous  radii  emerging 
from  the  peripheral  regions  converge.  At  the  same 
time,  a  superior  ganglion,  destined  to  be  the  brain,  is 
developed,  and  uniting  itself  to  the  axis,  becomes  in 
a  manner  the  crowning  of  the  edifice  thus  successfully 
perfected. 

From  this  moment  the  nervous  system  is  constituted 
as  a  central  force  destined  to  condense  in  its  plexuses 
sensitive  excitations,  in  order  to  transform  them  by  its 
own  metabolic  action  into  co-ordinated  motor  reactions. 
From  this  moment  the  living  forces  of  the  organism 
are  duly  subordinated  and  distributed  in  a  methodic 
fashion  ;  the  physiological  task  is  regularly  divided  ; 
one  group  of  elements  is  connected  with  sensibility,  one 
centre  with  motor-power,  and  another  with  the  functions 
of  organic  life. 

Sensation  is  henceforward  neatly  isolated  in  special 
regions  of  the  system,  neatly  collected  in  particular 
organs,  and  from  the  very  fact  that  it  is  attracted, 
like  an  electric  fluid,  by  means  of  nervous  conductors, 
from  the  peripheral  regions  towards  the  central,  it  be- 
comes a  disposable  mobile  force,  transmissible  to  a 
distance  like  dynamic  electricity. 

Once  concentrated  in  the  central  regions  of  the 
system,  it  thus  represents,  with  all  the  diverse  ele- 
ments of  which  it  is  composed,  a  true  synthesis  of 
all  the  partial  sensibilities  of  the  living  being,  and 
the  true  generating  element  of  its  living  and  feeling 
unity.  , 

The  phenomena  of  sensation  in  the  superior  animals 
are  not,  then,  simple  phenomena,  constituted  by  the 
mere  reaction  of  a  tissue  in  the  presence  of  external 
8 


go  THE  BRAIN   AND   ITS  FUNCTIONS. 

excitations  ;  they  are  the  complex  subordinated  opera- 
tions of  the  nervous  activity  which  require  the  partici- 
pation of  a  great  many  organs  successively  brought 
into  play,  in  order  to  arrive  at  their  complete  evolu- 
tion. We  shall  now  study  these  different  conditions  in 
F  accession. 


CHAPTER   XL 

EVOLUTION  OF  THE  PROCESS  OF  SENSIBILITY,  THROUGH 
THE  MECHANISM  OF  THE  NERVOUS  SYSTEM — UN- 
CONSCIOUS SENSIBILITY  —  CONSCIOUS  SENSIBILITY 
(SENSATION). 

The  nervous  system  being  constituted,  as  we  have  just 
explained,  by  a  central  axis,  plunging  by  its  lateral 
roots  into  the  surrounding  tissues,  and  crowned  at  its 
superior  extremity  by  a  central  ganglion,  the  brain, 
gifted  with  its  special  activity,  we  shall  now  see  how 
the  phenomena  of  sensibility,  existing  per  se  as  funda- 
mental histological  properties,  behave  in  presence  of  the 
machinery  which  the  nervous  system  places  at  their 
disposal  ;  how  they  become  incorporated  with  it ;  how, 
arriving  in  the  form  of  centripetal  excitation,  they  be- 
come refracted  in  the  plexuses,  reappearing  as  a 
centrifugal  reaction,  through  the  peculiar  influence  of 
the  new  media  they  have  put  in  requisition  ;  and  how 
at  last,  in  the  most  elevated  regions  of  their  journey, 
they  come  to  play  a  primary  part  in  the  evolution  of  the 
essential  phenomena  of  psycho-intellectual  activity. 

In  taking  their  departure  from  the  peripheral  regions 
of  the  nervous  system,  which  physiologically  represent 
the  frontiers  of  the  organism,  sensitive  impressions, 
wherever  they  may  have  originated,  once  implanted  in 


92  THE   BRAIN  AND   ITS   FUNCTIONS. 

their  tissues  in  the  form  of  vibratory  agitations,  follow 
their  natural  channels  towards  the  central  regions. 

Some  are  extinguished  in  certain  interposed  gang- 
lionic masses  ;  others  advance  further,  become  dis- 
persed in  the  grey  regions  of  the  cord  and  transformed, 
either  instantaneously  or  in  a  more  or  less  gradual 
manner,  into  excito-motor  reactions — these  being  the 
phenomena  of  unconscious  sensibility. 

Others,  finally,  endowed  with  an  altogether  special 
vitality,  pursue  tlieir  course,  converge,  mount  up  to  the 
sensoriiim  and  come  into  contact  with  the  psycho-intel- 
lectual operations  for  which  they  provide  the  indispens- 
able food — these  being  the  phenomena  of  conscious 
sensibility,  or  sensation,  to  which  they  give  birth. 

We  shall  successively  pass  in  review  the  mode  of 
genesis  and  distribution  of  these  two  special  groups  of 
sensitive  contingents. 

UnconscioiLs  Seiisibility. — Unconscious  sensitive  exci- 
tations are  derived  from  two  orders  of  peripheral 
plexuses : — 

1.  From  the  plexus  of  vegetative  life  of  the  sym- 
pathetic. 

2.  From  the  plexus  of  general  and  special  sensibility. 

These  latter  originate  in  common  with  the  excita- 
tions destined  to  ascend  to  the  sensoritiin  ;  but  they  are 
extinguished  on  the  way,  and  are  destined  to  produce 
reflex  actions  (automatic  actions)  in  the  interior  of  the 
plexuses  of  the  spinal  cord. 

I.  Sensitive  excitations  radiating  from  the  plexus  of 
vegetative  life,  if  we  take  them  from  their  origin,  only 
expand  within  a  limited  radius.  They  follow  the 
threads   of  the   sympathetic,  which  are  distributed  ad 


EVOLUTION   OF  SENSIBILITY.  93 

infiniUiDi  throughout  the  organism,  and  only  manifest 
their  presence  by  vaso-motor  phenomena,  capable  of 
modifying,  in  a  more  or  less  direct  manner,  certain 
branches  of  local  circulation. 

This  special  order  of  sensitive  impressions  is  con- 
densed in  special  ganglionic  masses,  which  represent 
small  local  centres,  and  are  the  primitive  types  of  the 
first  traces  of  a  nervous  system  in  the  lower  species. 

Sometimes  they  are  capable  of  radiating  to  a  dis- 
tance, and  thus  traversing  several  ganglionic  masses 
and  vibrating  even  as  far  as  the  grey  plexus  of  the 
spinal  cord,  of  which  they  thus  provoke  the  secondary 
activit}'.  Thus  it  is  that  the  sensibility  of  the  intestinal 
mucous  membrane  excites  the  secretion  of  the  juices' 
destined  to  co-operate  in  digestion  ;  that  the  sensi- 
bility of  the  uterus  laden  with  the  product  of  concep- 
tion leads  to  development  of  the  breasts ;  that  in 
abnormal  conditions  certain  abnormal  sympathies  are 
developed,  so  that  we  see,  for  instance,  the  irritation 
of  the  urethral  mucous  membrane  exercise  an  influence 
upon  certain  articular  surfaces  ;  and  that  the  irritation 
of  certain  peripheral  nerves  leads  to  the  sudden  occur- 
rence of  tetanic  phenomena  and  of  certain,  so  called, 
reflex  convulsions. 

Sometimes  also,  when  certain  peripheral  regions  in 
which  they  originate  are  intensely  affected,  and  have 
risen  to  the  pitch  of  pain,  the  excitations  of  sensi- 
bility become  capable  of  an  action  more  penetrating 
still,  and  even  of  reaching  the  sensorinm,  where  they  are 
perceived,  and  whither  they  carry,  as  it  were,  the  cry 
of  some  organ  of  vegetative  life  shaken  in  its  essential 
constitution. 


94  THE  BRAIN  AND  ITS  FUNCTIONS. 

In  general  we  may  say,  that  in  the  normal  sta^e  the 
impressions  of  vegetative  life  are  quite  silent  and  un- 
perceived  by  the  seiisoriiim.  The  wheels  of  the  inner 
life  of  the  human  machine  move  without  noise.  Few 
persons  except  medical  men,  are  aware  that  they 
possess  a  heart  provided  with  auricles  and  ventricles, 
which  contract  alternately  a  great  number  of  times  a 
minute  ;  a  stomach  which  secretes  a  juice  destined  to 
dissolve  the  azotised  elements  of  the  food  ;  a  pancreas 
designed  to  act  by  means  of  its  secretion  upon  the  fatty 
elements ;  intestinal  fibres  which  contract  alternately 
and  force  along  the  alimentary  bolus,  &c.  All  these 
phenomena  take  place  without  our  knowledge,  without 
our  having  the  slightest  notion  of  them,  and,  strange  to 
say,  those  facts  in  which  we  are  most  vitally  interested 
we  know  least  about ! 

But  is  this  really  the  case,  and  are  we  authorized  to 
think  that  the  different  forms  of  sensibility,  which  are 
in  activity  in  the  inmost  recesses  of  our  tissues,  really 
exist  without  having  a  sort  of  obscure  influence  upon 
our  sensoritLin,  analogous  in  this  respect  to  those  obscure 
rays  of  the  spectrum  which  our  eyes  do  not  behold,  and 
which  yet  have  so  real  and  indubitable  an  existence  ? 

This  does  not  seem  probable  to  me;  for  if  we  think 
how  instantaneously  a  visceral  pain  is  developed,  with 
what  clearness  this  pain  appears  when  a  calculus  is  fixed 
in  the  ductus  choledocJms,  or  when  a  foreign  body  is 
introduced  into  the  stomach  or  intestines,  where  it 
instantly  produces  painful  contraction,  we  cannot  help 
thinking  that  there  are  always  open  roads  between  the 
sensoriinn  and  the  regions  of  vegetative  life  ;  that  there  is, 
in  some  manner,  an  incessant  relation  between  these  two 


EVOLUTION  OF  SENSIBILITY.  95 

poles  of  sensibility  ;  and  we  must  recognize  the  fact  that 
there  is,  in  the  normal  state,  a  constant  though  uncon- 
scious afflux  of  the  partial  sensibilities  of  the  organism 
which  converge  towards  the  centres,  and  that  they  die 
away  there  in  silence  without  making  any  impression, 
yet  bringing  an  unconscious  notion  of  all  that  passes  in 
the  periphery  of  the  nervous  system.  We  see  every 
day  substances  with  which  we  are  constantly  in  contact, 
from  habit  pass  us  by  unperceived,  leaving  in  the 
sensoriinn  only  an  unseized  impression,  like  that  pro- 
duced by  the  atmospheric  air  on  the  respiratory  tract. 
Water  and  bread,  which  are  so  frequently  in  contact 
with  our  digestive  mucous  membranes,  furnish  us  with 
but  obtuse  impressions,  which  yet  are  consciously  per- 
ceived. 

It  is  then  probable  that  If  the  sympathetic  nerves  of 
vegetative  life,  starting  from  the  peripheral  regions,  form 
a  continuous  network,  of  which  the  converging  meshes 
more  and  more  nearly  approach  the  central  regions,  the 
histological  sensibility  which  they  abstract  from  the 
different  cell-territories,  amidst  which  they  originate, 
follows  the  same  natural  channels  ;  and  that  this  is  led 
up  to  reverberate  within  th^  sensoriinn,  in  a  disconnected 
obscure  manner  it  is  true,  yet,  nevertheless,  really  and 
permanently. 

We  cannot  fail  to  recognize  in  this  afflux  of  all  the 
diffuse  sensibilities  of  the  organism,  each  coming  to 
bring  to  the  sensoriuni  its  sensitive  note,  that  series  of 
generating  elements  which  are  designed  to  implant 
themselves  there  and  develop  in  us  that  essential  notion 
of  our  vital  being,  which  makes  us  feel  ourselves  live  in 
all  our  organic  molecules.     It  is  in  itself  nothing  but 


g6  THE   BRAIN   AND   ITS   FUNCTIONS. 

the  unconscious  notion  of  all  the  partial  sensibilities 
of  the  organism,  concentrated  in  this  grand  common 
reservoir. 

2.  Unconscious  excito-motor  impressions  arise,  with 
their  sister  conscious  impressions,  in  the  terminal  ex- 
pansions of  all  the  sensorial  and  sensitive  nerves. 

Mingled  with  their  fellows  they  enter  the  converging 
channels  which  are  open  to  them,  and  advance  together 
with  them  towards  the  central  regions  of  the  spinal  axis, 
having,  however,  first  traversed  the  chain  of  the  rachi- 
dian  ganglions. 

Arrived  at  the  grey  plexuses  of  the  spinal  axis,  they 
become  diffused  in  their  meshes,  excite  the  activity 
of  the  posterior  grey  regions  (which  represent,  as  it 
were,  a  great  common  sensor'iuin  of  unconscious  life, 
for  this  order  of  radiations),  and  pass  out  in  centri- 
fugal currents,  in  the  form  of  co-ordinated  motor 
reactions,  which  thus  represent  the  last  phase  of  a 
process  originating  in  the  purely  sensitive  regions. 

The  unconscious  excito-motor  sensibility,  transformed 
by  the  action  of  the  cells  belonging  to  the  automatic 
sensoriiLin,  by  this  very  circumstance  acquires  new 
properties. 

It  is  stored  up,  seized  upon,  and  condensed  on  the 
spot  in  the  tissue  of  the  organs  that  receive  it,  thus 
becoming  in  this  new  form,  like  a  projectile  rammed 
home  in  a  fire-arm,  capable  of  being  transmitted  to  a 
distance  along  the  centrifugal  conductors  radiating  from 
the  spinal  cord,  veritable  reophores  designed  to  favour  its 
dissemination  and  transport  it  to  a  long  distance,  even 
into  the  most  distant  and  eccentric  cell-territories. 

Thus   it  directs,   in    the   form   of  unconscious   optic 


EVOLUTION   OF   SENSIBILITY.  97 

excitations,  the  different  movements  of  rotation  of 
the  ocular  globes,  the  play  of  the  pupil,  the  accom- 
modation of  the  sight  to  different  distances ;  excites 
in  the  sphere  of  auditory  phenomena  the  unconscious 
movements  of  the  chain  of  little  bones,  to  graduate  the 
alternate  tension  and  relaxation  of  the  tympanic  mem- 
brane ;  co-operates  so  powerfully  in  the  complex 
and  varied  movements  of  mastication  and  deglutition  ; 
presides  over  the  succession  of  the  acts  of  erection  and 
ejaculation  ;  and,  in  a  word,  in  different  forms,  without 
the  intervention  of  the  sensorimn,  always  present,  always 
active,  assists  in  the  perfecting  of  the  sense  to  which  it 
is  attached,  favours  its  direction  towards  an  object, 
governs  the  play  of  its  mechanism,  so  as  to  obtain  the 
maximum  of  sensorial  impression,  and  thus  becomes 
the  indispensable  adjunct  of  conscious  impressions. 

It  is  still  this  unconscious  excito-motor  sensibility 
that  underlies  the  different  processes  of  the  respiratory 
phenomena  during  the  whole  term  of  our  lives,  from  our 
first  inspiration  to  our  last  sigh. 

It  maintains  the  play  of  the  motor  ganglions  of  the 
medulla  oblongata,  those  central  foci  of  innervation, 
whence  the  inspiratory  and  cardiac  muscles  draw  their 
unceasing  principle  of  activity.  It  expends  itself  at 
every  instant,  day  and  night,  in  the  continual  activity  of 
the  mysterious  laboratories  of  organic  life.  It  moreover 
plays  an  all-important  part  in  the  varied  series  of  our 
movements  of  progression,  in  all  those  of  bodily  exer- 
cise, in  the  methodical  motor  actions  that  we  insensibly 
bnng  to  perfection  by  practice  and  sustained  atten- 
tion— such  as  those  of  the  hand  in  drawing  or  writ- 
ing—  actions  which  though  at  hrst  conducted  with  tliC 


98  THE  BRAIN  AND   ITS  FUNCTIONS. 

conscious  participation  of  the  sensoriiim,  insensibly  come 
to  be  executed  under  the  sole  direction  of  the  excita- 
tions of  unconscious  sensibility. 

Thus,  then,  the  phenomena  of  automatic  life,  under 
whatever  form  they  present  themselves,  occur  of  them- 
selves and  by  virtue  of  the  intraspinal  transformation 
of  an  incident  excitation  of  reflex  sensibility  into  motor 
reaction  ;  and  this  without  the  sensorium  coming  into 


play,  without  the  intervention  of  conscious  sensibility, 
simply  as  a  return  effect  of  the  calling  into  activity  of 
process  of  unconscious  sensibility. 

But  although  the  phenomena  apparently  take  place 
thus,  being  evolved  without  the  effective  participation 
of  the  sensorium,  it  must  not  be  concluded  that  no  frac- 
tion whatever  of  these  excitations  is  radiated  towards 
it  and  extinguished  in  it,  somewhat  in  the  manner  of 
obscure  rays. 

It  is  very  probable  that  what  we  have  seen  to  occur 
as  regards  the  impressions  of  purely  vegetative  life  may 
occur  as  regards  this  special  order  of  excitations,  there 
being  probably  an  obscure  radiation  of  these  latter 
impressions  which  extends  to  the  sensormm,  and  thus 
transmits  to  it  the  vague  and  unconscious  notion  of 
the  activity  of  such  or  such  a  portion  of  our  muscular 
system. 

If  the  sensormm  indeed  be  not  directly  active  in  the 
infinite  series  of  motor  acts  that  we  accomplish  auto- 
matically, it  nevertheless  does  not  remain  a  complete 
stranger  to  the  operations  which  take  place  within  the 
organism.  If  it  does  not  interfere  directly  to  regulate 
the  play  of  such  or  such  an  organ,  to  move,  for  instance, 
the  crico-arytenoid  muscle  in  a  methodic  manner  for 


EVOLUTION  OF   SENSIBILITY.  99 

the  production  of  such  or  such  a  laryngeal  sound,  or  the 
accomplishment  of  such  or  such  an  act  of  digital  dex- 
terity ;  if  the  conscious  personality  cannot  discern  who 
are  the  workmen  at  work,  it  has  at  all  events  an  exact 
notion  of  the  operation  in  evolution,  knows  if  the  work 
be  accomplished,  and  the  requisite  muscular  exertion 
made.  We  do  not  feel  our  muscles  in  a  clear  and 
precise  manner  when  they  are  in  a  state  of  repose  ; 
but  when  they  are  in  activity,  this  new  condition  into 
which  they  are  thrown  develops  in  the  sensorium  a  new 
mode  of  existence,  so  that  the  unconscious  excito-motor 
sensibility  in  the  dynamic  state  indirectly  strikes  upon 
the  styisoriuin,  and  thus  becomes  a  new  element  destined 
to  become  absorbed  in  its  plexuses. 

Co?tscious  Sensibility  l^Sensatioii). — The  sensitive  exci- 
tations destined  to  become  conscious  and  enter  into  rela- 
tion with  the  phenomena  of  psycho-intellectual  activity, 
are  collected,  with  their  excito-motor  fellows  in  the 
peripheral  plexuses,  which  serve  as  a  region  of  emission 
for  both.  Starting  from  this,  and  taken  up  by  means  of 
the  converging  fibres,  they  pass  on  towards  the  central 
regions  of  the  axis,  are  concentrated  in  the  isolated 
ganglions  of  the  optic  thalamus,  and  are  afterwards 
radiated,  as  we  have  already  seen,  into  the  different 
regions  of  the  cortical  periphery.     (Fig.  6. — 9.  4.  14.) 

The  phenomena  of  conscious  sensibility  (or   sensa-  /; 
tion)  have  then  as  their  point  of  origin,  and  first  halting-  , 
place,  the   peripheral    regions   of  the   nervous   system..  \^ 
It  is  by  the  terminal  nervous  expansions  spread  out 
into  a  network,  open,  in  a  manner,  to  all  that  comes  to 
impress  it,  that  the  external  world  penetrates  and  be- 
comes incarnate  in  us.     And  for  this  a  special  faculty  for 


100  THE  BRAIN  AND   ITS   FUNCTIONS. 

receptivity  and  impressionability  in  the  nervous  element 
thus  impressed  is  in  the  first  place  necessary,  as  a  funda- 
mental and  indispensable  condition  of  the  phenomenon. 

In  a  word,  it  is  necessary  that  at  the  moment  the 
sensorial  network  receives  the  vibratory  excitation,  it 
shall  directly  participate  in  the  act  which  takes  place 
within  it.  It  must  become  active,  acquiesce — become  in 
a  manner  erect  ;  and  must,  by  a  species  of  vital  assimi- 
lation, convert  the  purely  physical  into  a  physiological 
excitation,  the  luminous  vibration,  for  instance,  into  a 
nervous  one. 

This  is  the  fundamental  act  of  which  we  shall  speak 
again  subsequently,  and  which  is  the  first  link  of  that 
chain  of  sensitive  phenomena  which  is  evolved  through- 
out the  nervous  system.* 

It  is,  in  fact,  a  vulgar  truth  which  reveals  itself  to 
simple  observation.  Every  one  knows  that  the  simple 
presence  of  a  physical  excitation  of  a  sensorial  organ 
is  insufficient  to  produce  a  conscious  impression,  and 
that  an  active  participation  of  the  sensorial  cell  in  the 
vibratory  movement  communicated  to  it  is  necessary. 
Open  the  eye  of  a  sleeping  man — the  luminous  rays 
fall  in  vain  upon  the  retina.  It  requires  a  certain 
time  before  the  nervous  cells  are  wakened  up  and 
enter  into  harmony  with  the  luminous  vibrations  which 

*  This  phenomenon  has  been  perfectly  described  by  Mathias  Duval.  "When 
the  retina  is  excited,"  he  says,  "  perception  is  not  immediate,  it  is  retarded  for 
a  very  short  period  ;  this  retardation  is  due  to  the  fact  that  it  requires  a  certain 
time  for  the  transformation  of  the  luminous  into  a  nervous  movement  to  take 
place.  Then  this  latter  movement  requires  an  interval,  exceedingly  short 
indeed,  to  be  propagated  along  the  optic  nerve  to  the  cerebral  centres  ;  and 
finally,  the  centres  of  perception  themselves  are  not  immediately  thrown  into 
agitation.  This  retardation  occupies  one-fiftieth  to  one-thirtieth  of  a  second." 
(Maihias  Duval,  "  These  dagregation,"  1873,  p.  132.) 


EVOLUTION   OF   SENSIBILITY,  10 1 

excite  them.  Pinch  the  skin  of  a  man  in  profound 
sleep,  cry  into  his  ear  under  the  same  conditions. 
There  is  the  same  apathy,  the  same  default  of  reaction. 
The  purely  physical  excitation  will  gradually  become 
deadened  if  tHerecome  not  m  its  train  a  purely  vital 
phenomenon  of  sensation,  which  is  developed,  by  a  sort 
of  active  prehension  of  the  physical  food  which  is 
oifTered  to  the  impressed  cell.* 

We  see,  then,  judging  by  what  takes  place  here  in 
this  first  phase  of  nervous  activity,  that  the  sensitive 
plexuses  of  our  whole  organism  are  all  either  isolatedly 
or  simultaneously  thrown  into  vibration,  according  to 
their  various  tonalities.  They  thus  become  like  vast 
vibratory  surfaces,  of  which  the  oscillations,  registered  as 
they  arrive,  are  incessantly  transmitted  to  the  other  parts 
of  the  system,  and  felt  in  the  sensoriiim  in  a  correspond- 
ing manner.  It  is  a  continuous,  regular,  imperative 
work,  which  is  accomplished  every  moment,  from  the 
peripheral  to  the  central  regions  of  the  system,  and  this 
uninterrupted  appeal  from  the  external  world  is  so  neces- 
sary, so  much  the  obligatory  condition  of  all  cerebral 
activity,  that  the  latter  ceases  at  once  when  its  means  of 
alimentation  from  without  are  cut  off  (loss  of  conscious- 
ness, sleep,  lethargy),  just  as  we  see  the  phenomena  of 
haematosis  cease,  when  the  atmospheric  air  suddenly 
ceases  to  enter  the  recesses  of  the  respiratory  channels. 

*  The  participation  of  the  sensorial  element  in  the  external  perturbation  is 
itself  only  a  species  of  fugitive  phenomenon,  having  a  transient  duration. 
When  the  duration  of  the  impression  is  too  prolonged,  transgressing  physio- 
logical limits,  it  brings  on  a  period  of  fatigue  of  the  receptive  element,  and 
ceases  to  produce  any  effect.  Thus  the  sensibility  of  the  retina  is  rapidly 
blunted.  When,  for  instance,  we  look  for  a  long  time  at  a  white  spot  on  a 
black  surface,  and  afterwards  look  at  a  white  surface,  we  imagine  that  wa 
see  a  black  spot  upon  this,  the  retma  having  become  insensible  to  white. 


CHAPTER  III. 

INTRA-CEREBRAL    PROPAGATION    OF    THE    PROCESSES 

OF  SENSIBILITY. 

Sensitive  impressions  pursuing  their  course  are,  as  we 
have  already  seen,  condensed  in  the  masses  of  grey 
matter  in  the  optic  thalami. 

These  masses  of  grey  matter  represent,  then,  in  the 
general  economy  of  the  nervous  system,  a  species  of 
point  of  convergence,  or  cross-roads,  and  the  penulti- 
mate halting-place  where  impressions  from  the  external 
world  are  united  before  being  radiated  towards  the 
peripheral  cortical  regions. 

But  as  regards  these  different  kinds  of  sensitive  ele- 
ments which  come  flowing  towards  the  grey  ganglions  of 
the  optic  thalami,  these  latter,  which  receive  them  into 
their  mass,  give  them  each  an  isolated  territory — so  that 
that  division  of  labour  of  which  we  have  already  seen  an 
example  in  the  progressive  evolution  of  the  nervous 
system,  here  seems  to  receive  a  new  confirmation,  since 
we  see  the  phenomena  of  sensibility  divided,  like  white 
light,  into  isolated  fascicles,  each  fascicle  having  a  special 
receptive  apparatus  reserved  for  itself  exclusively. 

Thus  purely  sensitive  impressions  have  a  central  gang- 
lion where  they  are  isolatedly  condensed  (Fig.  6 — 9.); 
it  is  the  same  for  the  optic,  olfactory,  and  acoustic  im- 


PROCESSES  OF   SENSIBILITY.  IO3 

pressions  and  finally  the  excitations  of  vegetative  life 
also  find  a  cell-territory  specially  appropriated  to  their 
reception, — so  that  as  the  processes  of  sensibility  become 
perfected,  as  they  penetrate  more  deeply  into  the  interior 
of  the  nervous  system  we  find  them  splitting  up,  divid- 
ing into  elementary  fascicles,  each  gifted  with  dissimilar 
specific  properties,  and  yet  united  among  themselves 
by  the  common  bonds  of  their  origin  and  evolution. 

After  radiating  through  the  cerebral  white  fibres,  into 
the  difi"erent  departments  of  the  cortical  substance,  the 
same  phenomena  of  division  of  labour  again  occur,  and 
we  may  directly  observe  that  the  regions  in  which  the 
dissemination  of  auditory  impressions  takes  place  are 
different  from  those  where  that  of  the  olfactory,  visual, 
etc.,  takes  place.  So  that  each  isolated  region  of  the 
brain  has  also  to  work  and  develop  its  specific  energies 
in  isolation.    {See  Fig.  6 — 4.  9.  14.  and  Fig.  5 — 7.  8.  10.) 

When  the  sensitive  excitations,  whatever  they  may  be, 
have  been  launched  into  the  midst  of  the  plexuses  of  the 
cortical  layer,  they  find  there  also  sensitive  nervous 
apparatuses  prepared  to  receive  and  absorb  them,  and 
thus  co-operate  in  the  various  processes  in  evolution. 

We  have  indeed  already  studied  the  remarkable  dis- 
position of  the  cells  of  the  cortex  {see  Fig.  i .),  which  are 
arranged  in  isolated  zones,  stratified  like  the  layers  of 
the  crust  of  the  earth,  and  thus  constitute  a  continuous 
network  of  which  all  the  organically  connected  molecules 
are  arranged  so  as  to  vibrate  in  unison,  and  to  propagate 
the  nervous  undulations,  either  vertically  or  laterally 

On  the  other  hand,  those  myriads  of  nerve-cells,  ag- 
glomerated into  a  continuous  whole  in  the  sub-meningeal 
regions  of  the  cortical  substance,  are  themselves  essen- 


I04  THE  BRAIN   AND   ITS   FUNCTIONS. 

tially  sensitive.  They  are  living,  impressionable,  and 
gifted  in  the  highest  degree  with  that  vitality  which 
characterizes  the  nervous  elements :  and  accordingly, 
when  the  perturbation  from  the  external  world,  trans- 
formed by  the  metabolic  action  of  the  optic  thalami, 
comes  to  reverberate  within  them,  they  are  perturbed  in 
their  turn,  and  are  in  a  manner  thrown  into  a  condition 
of  erethism,  just  as  the  peripheral  plexuses  were  when 
first  agitated  by  the  external  excitation.* 

Thus  it  is  that  the  sensitive  excitations  awaken  the 
activity  proper  to  the  elements  of  the  cortical  substance  ; 
that  these  are  brought  into  play  ;  and  that  the  sensitive 
process,  like  a  force  which  is  incessantly  transformed, 
loses  by  degrees  its  primordial  character  as  it  advances 
and  enters  a  new  territory. 

We  see  then  how  gradually  the  processes  of  sensibility 
are  transformed  by  incorporating  themselves  more  and 
more  with  the  organism;  how,  starting  as  simple  physical 
elements,  they  end  by  becoming,  in  the  last  term  of 
their  long  course,  a  living  excitation,  more  and  more 
animalized  and  intellectua  ized  by  the  special  activities 
of  the  different  media  which  they  have  successively  called 
into  action.  In  this  respect  they  are  quite  comparable  to 
those  physical  phenomena  by  virtue  of  which  we  see 
the  luminous  rays  which  pass  through  our  optical  instru- 
ments become  subject  to  the  modifying  influence  of  the 
media  they  traverse — become  concentrated,  refracted, 
unequally  diffused  ia  secondary  elements,  to  present 
themselves  finally  to  our  visual  sensibility,  perfected, 
purified,  separated,  and  with  their  maximum  of  effect. 

Genesis  of  the  Notion  of  Personality  and  of  Moral 

•  Account  of  the  experiments  of  Scliiff,  p.  '^'j. 


PROCESSES   OF   SENSIBILITY.  IC5 

Sensibility. — The  processes  of  sensibility  have  not  for 
f;heir  sole  object  the  transformation  of  external  excita- 
tions ;  they  contribute  in  a  much  more  effectual  manner 
to  operations  of  great  delicacy,  which  are  designed  to 
co-operate  in  the  genesis  of  the  notion  of  our  individual 
personality. 

It  is,  indeed,  throjgh  the  awakening  of  the  activity 
of  the  sensibility  diffused  throughout  the  different 
regions  of  the  organism — vegetative  as  well  as  excito- 
motor  sensibility  —  that  this  notion  is  engendered, 
developed,  and  maintained  constantly  active  and  alive 
in  us. 

It  follows,  indeed,  as  a  natural  ccnsequence  of  what 
we  have  already  indicated,  that  everything  in  us  which 
is  sensitive — every  fibre  which  vibrates,  every  sensorial 
plexus  which  becomes  erethised — produces  a  vibration 
which  is  concentrated  in  the  plexuses  of  the  cortical 
substance,  and  finds  in  their  essential  structure  a  vast 
common  reservoir,  the  veritable  scnsorinni  commime  into 
which  all  the  excitations  collected  in  the  periphery 
separately  flow,  and  in  which  they  remain  latent. 

The  result,  as  regards  the  secondary  reactions  of  this 
scnsorinni,  of  the  general  concentration  in  these  plexuses 
of  all  the  diffuse  sensibilities  of  the  organism,  is  naturally 
that  all  the  sensibilities  of  the  peripheral  regions  of  the 
nervous  system,  drained  from  the  essential  structure  of 
our  tissues,  of  our  flesh,  mucous  membranes,  viscera — in 
a  word,  of  our  whole  organism— and  conducted  along 
the  converging  nervous  filaments,  as  the  electric  fluid  is 
along  the  wires  which  transport  it  to  a  distance,  inevita- 
bly travel  towards  the  central  regions  of  the  system, 
towards  the  sensoriuui  conininnc,  where  they  are  simul- 
9 


106  THE  BRAIN   AND   ITS   FUNCTIONS. 

taneously  distributed  ;  and  that  these  conceptive  regions 
of  the  sensorimn  represent,  as  it  were,  at  the  other  pole, 
the  sensitive  foci  correlated  to  the  peripheral  regions  in 
agitation. 

AW  these  modes  of  sensibility,  whatever  be  their 
origin,  are,  then,  physiologically  transported  into  the 
sensoriiim,  and  there  find  a  symmetrical  region  which 
vibrates  in  unison  with  their  peripheral  tonality ;  so  that 
from  fibre  to  fibre,  from  sensitive  element  to  sensitive 
element,  our  whole  organism  is  sensitive,  our  whole 
sentient  personality,  in  fact,  is  conducted,  transported 
just  as  it  exists,  as  a  series  of  isolated  currents,  into  the 
plexuses  of  the  sensoriuin  commune.'^  • 

There  we  are  represented  in  detail,  there  all  our 
sensitive  elements  are  condensed,  fused,  and  anasto- 
mosed into  an  inextricable  unity — a  unity  which  is  itself 
only  an  expression  of  the  organic  connection  of  the 
underlying  nervous  plexuses.  There,  in  a  word,  the 
synthesis  of  all  our  dispersed  sensibilities,  which  are 
united  in  a  limited  space  and  yet  faithfully  reproduced, 
takes  place.     There  our  personality  lives  and  feels. 

Here,  by  means  of  the  conductility  of  sensitive  ex- 
citations and  the  intervention  of  the  nervous  system, 
which  represents  in  the  truest  sense  an  organ  of  per- 

*  Tlie  conductility  and  disperoion  of  sensibility  in  the  j^wjct/wot,  by  means 
of  the  nerve-fibres,  is  so  real,  that  in  persons  who  have  suffered  amputation, 
when  any  irritation  attacks  the  stump  and  engages  the  sensitive  nerves,  it 
immediately  awakes  and  develops  in  the  sensorium  the  old  impressions  in  a 
posthumous  form.  It  is  not  simply  the  painful  state  of  the  sensitive  nerves 
that  the  patient  feels,  it  is  also  the  resurrection  in  the  serjsorium  of  a  portion  of 
himself,  in  consequence  of  the  persistence  of  the  conductors  which  formerly 
supported  it  and  in  which  this  sensitive  portion  of  his  personality  was  incar- 
nate. {See  MuUe",  "  Physiologie,"  vol.  i.  p.  598  ;  Sensations  experienced  by 
persons  after  amputation.) 


PROCESSES  OF  SENSIBILITY.  I07 

fectionment  implanted  in  the  organism — something 
takes  place  quite  like  what  we  see  in  a  camera  obscura, 
when  we  see  images  of  the  external  world  projected 
upon  a  screen  which  presents  only  a  limited  plane 
surface.  The  magnifying  lenses  of  the  object-glass, 
the  interposed  media,  have  conducted  and  directed 
the  luminous  rays  in  such  a  manner  that  they  are  pre- 
sented to  the  eyes  spread  out  over  a  limited  surface,  with 
all  their  gradations  of  tint  and  colour,  and  with  the 
relations  they  have  in  nature. 

The  external  world  is  thus  projected  to  a  distance  and 
conducted  into  another  region  than  that  whence  it  is 
derived,  just  as  the  sensitive  excitations  of  the  organism 
are  dra.'ned  off,  condensed,  and  transported  to  a  distance 
by  the  nervous  apparatuses  which  project  them  into  the 
scmsoriiiniy  and  thus  permit  of  their  being  grouped 
according  to  their  natural  affinities. 

Moral  Sensibility. — When  the  peripheral  impressions 
are  dispersed  in  the  plexuses  of  the  sensoriiun,  and  the 
cerebral  cell  is  called  into  play,  a  new  series  of  pheno- 
mena is  developed.  This  depends  on  the  spontaneous 
reactions  of  the  elements  of  the  sensoriiim  which  are  in 
agitation,  and  which  vibrate  in  unison,  and  become 
erethised  in  consequence  of  the  arrival  of  an  external 
impression. 

At  this  moment  a  phenomenon,  quite  similar  to  that 
which  occurred  in  the  peripheral  regions,  takes  place 
when  the  sensorial  plexuses  are  unexpectedly  agitated. 

This  process,  which  leads  to  the  transformation  of  the 
incident  sensorial  im.pression  into  a  physical  excitation, 
is  not  accomplished  coldly  and  passively.  The  thou- 
sands of  cerebral  cells  of  the  sensorium  commune  that 


I08  THE   BRAIN   AND   ITS   FUNCTIONS. 

have  been  unexpectedly  awakened  acquiesce  in  it  in  their 
own  manner.  They  react  in  a  specific  manner,  and,  like 
their  partner-cells  situated  at  the  antipodes  in  the  sen- 
sorial plexuses,  they  react  according  to  the  manner 
in  which  their  natural  affinities  have  been  excited. 
According  as  the  excitation  has  gratified  or  wounded 
their  profound  sympathies  they  are  agreeably  or  dis- 
agreeably impressed. 

A  new  phase,  therefore,  at  this  moment  appears  in 
the  evolution  of  sensibility,  a  new  element  comes  into 
play,  which  speaks,  and  is  excited.  This  is  the  specific 
sensibility  of  the  elements  of  the  sazsoriuin,  the  emo- 
tivity which  is  disengaged  from  the  cortical  substance  ; 
and  it  comes  into  play  in  a  necessary,  involuntary, 
automatic  manner,  by  the  simple  awakening  of  the 
elementary  properties  of  the  regions,  engaged.  We 
all  know  how  passively  we  receive  the  excitations  which 
agitate  us,  and  how  little  free  we  are  to  feel  or  not  to 
feel  impressions  from  without. 

This  form  of  sensibility  which  runs  riot  in  spite  of  us, 
these  plexuses  of  the  sensoriiim  commwie  which  com- 
prehend in  themselves  all  the  diffuse  sensibilities  of  the 
organism,  represent,  then,  a  sphere  of  nervous  activity 
in  erethism,  always  living,  always  feeling,  in  the  bosom 
of  which  our  total  personality  lives  and  vibrates. 
There,  in  this  mysterious  dwelling,  it  is  in  perpetual 
intercourse  with  the  perpetual  movement  of  the 
operations  of  cerebral  life.  There,  according  to  the 
nature  of  the  excitations  that  agitate  it,  it  finds  its 
keenest  pleasures  and  deepest  pains — the  passionate 
enthusiasm  which  exalts  it,  the  anguish  which  depresses 
it      There  vibrate  the  sensitive  chords  of  our  human 


PROCESSES   OF   SENSIBILITY.  I09 

nature,  which,  alternately  tightened  and  relaxed,  express 
the  different  pitches  of  the  emotions  that  set  them 
vibrating.* 

The  phenomena  of  moral  sensibility,  conceived,  as  we 
have  just  done,  as  a  purely  physiological  synthesis  of  all 
the  nervous  activities,  consist  then  in  a  series  of  regular 
processes,  executed  hy  the  organism  at  its  own  expense, 
and  resulting  from  the  harmonic  consensus  of  all  its 
parts. 

They  present  these  two  very  significant  peculiarities, 
which  give  them  a  supreme  importance  in  the  sum  of 
the  acts  of  cerebral  life  : 

I..  On  the  one  hand,  they  are  sustained  and  vitalized 
by  means  of  former  excitations  ;  they  live  upon  accu- 
mulated memories  incessantly  reviving. 

2.  On  the  other  hand,  they  are  stirred  up  and  kept 
awake  by  the  intervention  of  the  intellectual  regions, 
with  which  they  are  in  perpetual  intercourse. 

I.  Thus  while  the  peripheral  plexuses  are  only  gifted 
with  a  limited  power  of  retaining  the  external  vibra- 
tions which  have  called  them  into  action  ;  the  cerebral 
elements,  on  the  contrary,  have  this  power  in  a  very 
high  degree.  As  we  shall  see  further  on,  they  can 
store  up  the  impressions  which  affect  them,  as  phos- 
phorescent bodies  or  collodion  plates  store  up  solar 
rays,  and  retain,  for  a  greater  or  less  period,  a  record 
of  the  elements  which  have  more  or  less  strongly 
affected  them. 


*  The  pages  which  Guislain  has  devoted  to  this  subject  will  be  read  with 
interest;  and  it  will  be  seen  that  he  had  a  presentiment  of  the  physiological 
evolution  of  the  phenomena  we  are  now  describing.  (Guislain,  vol.  ii.  "  Lemons 
sur  les  Phr(^nopathies,"  p.  12.) 


no  THE  BRAIN  AND  ITS  FUNCTIONS. 

The  result  of  the  awaking  of  this  new  property,  as 
regards  the  evolution  of  moral  sensibiHty,  is  that,  once 
an  excitation  has  been  produced  in  the  sensorium, 
once  it  has  been  incarnated  with  a  special  coefficient  of 
pleasure  or  pain,  it  remains  there  like  a  phosphorescent 
gleam,  and  survives  itself  as  a  posthumous  record. 

Suppose  an  object  or  a  person  has  induced  in  us  a 
movement  of  expansion  or  joy,  the  memory  of  the  joy 
perceived  will  survive  in  our  sensorium^  and  will  be  re- 
awakened by  the  memory  of  the  object  or  person  who 
has  provoked  this  pleasant  emotion.  In  the  same  way, 
conversely,  the  memory  of  an  insult,  an  injustice,  a 
moral  pain,  persists  in  us,  and  remains  attached  to  the 
person  or  the  object  that  has  been  the  cause  of  it. 
The  emotion  is  united  to  this  memory  to  such  an  extent 
that  it  is  enough  to  think  of  it  to  cause  an  unpleasant 
emotion  in  us. 

We  know  that  when  we  voluntarily  recall  the  image 
of  touching  scenes  at  which  we  have  been  present,  their 
reminiscences  evoke  in  us  emotions  similar  to  those  we 
experienced  at  the  period  when  they  actually  occurred. 
We  knovv  also  how  profoundly  the  anniversaries  of 
private  griefs  or  public  calamities  affect  our  natural 
sensibility. 

We  may  say,  then,  that  moral  sensibility  is  engen- 
dered by  the  fact  of  the  arrival  and  persistence  of 
impressions  in  the  sensoriinn.  It  is  a  phenomenon  of 
memory,  the  memory  of  the  heart,  as  has  been  said, 
which  lives  and  develops  itself  in  us,  and  is  only  sus- 
tained by  means  of  old  emotions,  which,  always  more 
or  less  lively,  are  always  alive  and  always  ready  to 
cause    a    sympathetic   thrill   throughout   the    sensitive 


PROCESSES   OF   SENSIBILITY.  m 

plexuses  of  our  inmost  personality.  Moral  sensibilit)^, 
then,  becomes  the  resultant  of  all  our  joys  and  sorrows, 
and  the  sympathetic  link  which  unites  our  present  to 
our  former  emotions. 

2.  Moral  sensibility  finds  also  in  the  intervention  of 
intellectual  activity  a  new  power,  which  excites  it, 
makes  it  active,  and  maintains  it  in  a  perpetual  state 
of  erethism. 

It  is,  in  fact,  most  interesting  to  observe  the  important 
part  that  the  intellect  plays  in  the  evolution  and  main- 
tenance of  the  freshness  of  our  natural  sensibility. 

If  our  sensibility  finds  an  individual  existence  in  the 
plexuses  of  the  sensorium,  we  may  say  that  it  is  enlight- 
ened, directed,  educated  only  by  the  direct  participa- 
tion of  the  intellect  and  its  manifestations.  Without 
the  intervention  of  the  intelligence,  our  sensibility,  with 
all  its  riches,  would  be  nothing  but  an  inert  brute  force, 
diffuse  and  completely  undisciplined. 

It  is,  in  fact,  the  forces  of  the  intellect,  always  active 
in  the  form  of  discernment,  which  make  us  reflect  upon 
the  choice  of  things  or  persons  which  have  more  or  less 
affected  our  sensorhim.  It  is  because  we  have  an 
acquired  experience  of  certain  persons  or  things  that 
we  can  give  them  our  confidence.  To  choose  our  rela- 
tionships and  friendships,  and  thus  to  make  repeated 
rapid  diagnoses  of  men  and  things,  is  an  entirely  intel- 
lectual operation,  which  illumines  with  the  light  of  our 
reason  the  too  often  involuntary  impulses  of  our  natural 
sensibility. 

Again,  it  is  by  virtue  of  the  same  intimate  participa- 
tion of  the  intelligence  in  the  acts  of  our  sensitive  life, 
that  a  written   page,  a  word,  a  sound,  an  appearance, 


112  THE   BRAIN   AND   ITS   FUNCTIONS. 

can  suddenly  thrill  all  the  emotional    regions  of   our 
being  in  an  agreeable  or  disagreeable  manner. 

When  I  receive  a  telegram  or  a  sudden  piece  of  news 
\\hich  throws  me  into  trouble  and  consternation — when 
the  reading  of  a  comic  author  develops  hilarity  in  me, 
it  is  still  the  direct  intervention  of  the  intellect,  and 
the  intellect  alone,  which  excites  and  develops  these 
sad  or  joyful  impulses  of  my  moral  sensibility.  It  is 
because  I  comprehend — because  my  intellect  works  and 
im.mediately  interprets  the  value  of  the  written  charac- 
ters—that I  remember  that  each  word  expresses  a 
thought,  and  determines  a  sentiment  of  a  certain 
pitch.  It  is,  then,  always  the  intellect,  active  and 
present,  that  in  the  presence  of  a  sudden  excitation, 
ab  externo,  awakes,  and  causes  emotions  appropriate  to 
the  external  phenomena  which  they  symbolize,  to  arise 
in  the  sensoriiivi.^ 

In  the  same  series  of  facts,  when,  for  instance,  in  a 
foreign  country  I  salute  with  emotion  the  appearance  of 
the  national  flag,  which  is  displayed  before  me  as  a 
symbol  of  my  distant  country,  I  surely  do  not  see  in  it 
merely  a  piece  of  many-coloured  bunting.  No — at  that 
moment  a  series  of  associated  memories  is  awakened  in 
me.  I  involuntarily  think  of  a  long  past  of  glory, 
honour,  and  devotion,  which  is  unrolled  with  its  folds, 
and  of  the  patriotic  solidarity  which  unites  me  with 
those  who  defend  it  ;  and  thus,  from  idea  to  idea,  from 
Tiemcry  to  memory,  all  the  elements  of  my  moral  sen- 

*  This  connection  between  tlie  intellectual  and  emotional  regions  is  so  inti- 
mate, that  in  dreams,  when  the  intellectual  regions,  abandoned  to  their  free 
lutomatic  activity,  engender  the  strangest  conceptions,  we  are  sometimes  seized 
m\\\  impressions  of  sudden  terror  and  overwhelmed  in  consequence  of  certain 
errific  apparitions. 


PROCESSES   OF    SENSIBILITY.  II 3 

sibilli-y,  awakened  by  a  single  physical  impression  of  an 
external  symbol,  are  thrilled,  one  after  another,  because 
this  external  symbol  has  awakened,  in  the  regions  of 
intelligence,  old  ideas,  and  national  memories. 

Thus,  then,  the  activity  of  the  intellectual  regions 
excites,  and  incessantly  keeps  our  moral  sensibility 
permanently  awake  within  us  ;  while  at  every  instant 
of  the  day,  in  this  incessant  working  of  all  our  mental 
activities,  the  intellect,  present  everywhere,  watches  over 
all,  co-ordinates  memories,  regulates  and  stimulates  the 
impulses  of  sensibility,  and  thus  becomes  the  natural 
bridle  which  restrains  them,  as  far  as  this  can  be  done, 
within  the  limits  of  right  and  reason.*  This  is  so 
true,  indeed  the  energy  of  moral  sensibility  is  so 
closely  connected  with  the  energy  of  the  intellectual 
faculties,  that  when  the  latter  are  attacked,  moral  sen- 
sibility inevitably  falls  into  decay.  We  often  observe, 
indeed,  that  in  demented  old  men  whose  intellectual 
faculties  are  considerably  impaired,  the  impulses  of 
moral  sensibility  simultaneously  decay,  or  are  more  or 
less  profoundly  injured. 

*  It  is  this  direct  participation  of  intellectual  activity  in  the  phenomena 
of  sensibility  proper,  that  produces  the  different  modes  of  feeling  in  men 
according  to  their  different  degrees  of  intellectual  culture,  their  mode  of  life, 
and  the  hereditary  conditions  of  organization  they  may  present.  'I  he  cultivated 
ni.in  will  be  moved  by  spectacles  different  from  those  which  please  uncultivated 
and  gross  men.  The  refined  in  intellect  have  tueit  special  delicacies  of  senti- 
ment and  modes  of  enjoyment  which  are  uiiknown  to  the  vulgar. 


CHAPTER   IV. 

PERTURBATIONS   OF   SENSIBILITY. 

Physical  Pain. — The  phenomena  of  sensibility,  like  al! 
phenomena  of  vital  activity,  are  susceptible  of  alternate 
lowering  and  exaltation,  and  of  presenting  maxima  and 
7ninima  of  oscillation,  in  the  interval  between  which 
their  average  periods  are  comprised. 

Thus,  when  sensibility  is  locally  annihilated,  when 
the  histological  tissues  are  affected  with  a  species  of 
local  torpor,  anaesthetic  phenomena  present  themselves. 
When,  on  the  other  hand,  the  contrary  phenomena  occur, 
when  histological  vitality  rises  several  degrees  to  a  state 
of  cellular  excitement,  and  the  nervous  elements  reach 
a  condition  of  continuous  erethism — then  manifestations 
of  hyperaesthesia  or  pain  occur.  In  these  two  cases 
phenomena  connected  with  the  natural  sensibility  of  the 
nervous  elements  are  always  present,  and,  as  it  were,  rise 
from  zero  to  one  hundred  degrees. 

The  processes  of  anaesthesia  and  pain  appear  to 
develop  like  those  of  normal  sensibility,  independently 
of  any  nervous  plexus  which  underlies  them,  from  the 
simple  fact  of  the  existence  of  a  cell  capable  of  living 
and  feeling. 

It  is  certain,  indeed,  that  in  sensitive  cells  sensibility 
becomes  obtuse  and  grows  feeble  under  the  influence 


PERTURBATIONS   OF   SENSIBILIIY.  II5 

of  certain  special  conditions :  chloroform  makes  their 
reaction  impossible.  Certain  narcotic  substances  also 
appear  to  have  a  stupefying  action  on  the  sensibility  of 
certain  plants.  It  is  certain  again,  that  the  sensibility  of 
vegetables  is  perverted  when  they  are  thwarted  as  regards 
their  natural  evolution,  and  do  not  fmd  in  the  soil  with 
which  they  are  furnished  conditions  favourable  to  their 
physiological  nutrition.  It  is  certain  that  they  suffer 
also,  as  it  is  popularly  said,  and  that  their  sensitive  tissues, 
which  are  impressionable  by  external  agencies,  have  to 
contend  against  wounds  or  with  enemies  of  all  kinds 
belonging  to  the  animal  and  vegetable  kingdoms,  which 
under  the  form  of  parasites,  oidium,  phylloxera,  etc., 
fasten  upon  them  and  attack  them  even  in  their  roots, 
in  the  very  sources  of  life,  thus  inflicting  upon  them  the 
same  calamities  we  may  see  raging  among  individuals 
of  the  animal  kingdom. 

Pain,  from  the  very  fact  that  It  expresses  a  purely  vital 
action  inherent  in  every  living  cell,  vegetable  as  well  as 
animal,  is  therefore  the  physiological  equivalent  of  the 
individual  sensibility  of  that  same  cell  in  conflict  with 
the  surrounding  medium  which  impresses  it  painfully. 
It  exists  wherever  there  is  a  cell  capable  of  living 
and  feeling,  and  independent  of  the  existence  of  any 
nervous  element.  Between  the  simple  histological  Irrit- 
ability of  any  anatomical  element  whatever,  which  is 
the  rudimentary  form  under  which  it  presents  itself  at 
first,  and  the  most  exquisite  expressions  of  sensibility 
in  superior  beings,  there  are  merely  infinite  degrees  of 
sensitive  vibrations  which  mark  Its  difl"erent  modes. 

Just  as  we  see  a  metal  rod  placed  In  a  blazing  furnace 
grow  hot  by  degrees,  and  in  proportion  as  the  undula- 


Il6  THE  BRAIN   AND   ITS   FUNCTIONS. 

tions  of  the  caloric  become  more  and  more  frequent, 
pass  in  succession  through  the  shades  of  bright  red, 
dark  red,  and  white  heat,  and  develop  as  it  grows 
hot  both  heat  and  hght ;  so  the  Hving  sensitive 
ceils,  in  presence  of  the  excitations  which  affect  them, 
undergo  progressive  exaltation  as  regards  their  natural 
sensibility,  arrive  at  a  period  of  erethism,  and  with  a 
certain  number  of  vibrations  disengage  pain,  as  the  phy- 
siological expression  of  this  sensibility  super-heated 
to  a  white  heat.  This  is  so  true — the  phenomena  of 
pain  are  so  really  an  act  of  vital  reaction,  that  not 
merely  the  awakening  of  sensibility  but  a  certain  ten- 
sion of  it,  is  its  necessary  condition.  When  the  nervous 
plexus  is  torpid,  anaesthetic,  pain  cannot  be  developed. 
Suffering  is  not  a  thing  of  the  will — to  suffer  we  must 
feel. 

All  physicians  know  what  curious  phenomena  the 
skin  of  hysteric  patients  often  presents  in  this  respect. 
You  may  pinch  them,  prick  them,  apply  bi/rning  sub- 
stances to  the  surface  of  the  body  ;  the  patients  feel 
nothing  save  the  simple  contact  of  the  substances 
applied  ;  their  sensitive  plexuses,  stricken  with  a  species 
of  torpor,  are  incapable  of  erection,  becoming  excited 
and  disengaging  pain. 

In  producing  local  anaesthesia  we  obtain  a  similar 
condition  of  the  sensitive  plexuses,  and  prevent  the 
evolution  of  pain.  When  the  anaesthetic  agent  is 
applied  it  acts  locally  upon  the  iadividual  sensibility 
of  the  nerves  of  the  region.  It  chills  them  in  a  man- 
ner, hinders  them  from  becoming  heated,  as  regards  the 
excessive  production  of  painful  vibrations,  and  main- 
tains them  at  the  low  pitch  of  general  sensibility.     The 


PERTURBATIONS   OF   SENSIBILITY.  II7 

anaestheticlzed  regions,  in  fact,  cease  to  disengage  pain, 
while  they  are  still  conductors  of  sensitive  impressions. 

Pain  being  only  the  expression  of  the  histological 
sensibility  of  the  nervous  elements  risen  to  an  extra- 
physiological  pitch,  we  can  understand  how,  being 
always  identical  with  itself  as  regards  its  genesis,  it 
may  reveal  itself  in  a  different  manner  according  to 
the  different  nature  of  the  nervous  plexus  thrown  into 
ao^itation. 

Thus  pain  presents  itself  in  various  modes  according 
as  it  affects  such  and  such  a  sensorial  plexus.  If  it  be 
the  retina  which  is  affected,  we  know  that  when  light  is 
too  intense  its  sensibility  is  developed  to  excess,  and 
leads  to  a  reverberation  excessively  painful  for  the  sen- 
sorimn.  It  is  the  same  with  the  acoustic  nerves,  when 
violent  and  s'rident  sounds  produce  contusions  of  their 
natural  sensibility.  The  olfactory  and  gustatory  plex 
uses  have  also  their  own  forms  of  suffering,  and  every- 
one knows  how  painfully  the  contact  of  bitter  and 
acrid  substances,  or  that  of  foetid  emanations,  affects 
the  sensorial  plexuses  thus  brought  into  play.  Finally, 
when  our  viscera  are  attacked  in  their  sensitive  ele- 
ments, we  all  know  that  they  complain  in  their  own 
fashion  to  the  scnsorhim,  that  they  reveal  their  suffer- 
ing in  a  peculiar  manner,  and  that  the  manifestations 
of  pain  vary  with  the  tissues  engaged,  the  regions 
invaded  ;  that,  in  a  word,  the  semeiology  of  pain,  as 
regards  its  different  characters  and  modes,  has  a  special 
physiognomy  wliich  all  physicians  can  appreciate. 

If  we  now  pass  to  the  examination  of  the  processes  of 
pain  in  the  central  leg'.ons  of  the  nervous  system,  we 
shall  see  that  they  are  developed  in  a  manner  similar  to 


V 

Il3  THE  BRAIN   AND   ITS    FUNCTIONS. 

that  we  have  just  explained,  and  that  the  morbid  re- 
actions of  the  sensorium  have  a  method  similar  to  that 
of  the  morbid  processes  of  the  peripheral  regions. 

The  plexuses  of  the  sensormm,  in  the  substance  of 
which  sensitive  impressions  are  diffused,  are  normally 
insensible,  like  our  nerves,  which,  when  in  activity, 
silently  transmit  and  elaborate  sensorial  impressions, 
without  our  having  a  notion  of  all  their  minute  opera- 
tions. 

It  is  not  always  so.  Just  as  the  peripheral  plexuses 
are  susceptible  of  exaltation  in  presence  of  too-energetic 
vibratory  excitations,  or  by  the  occurrence  of  a  local  dis- 
turbance of  their  habitual  state  of  existence — so  the 
plexuses  of  the  sensorimn  are  susceptible  of  excessive 
heating,*  and  of  exaltation  when  a  too-vivid  peripheral 
impression,  or  a  too-prolonged  excitation  comes  to  rever- 
berate through  their  meshes,  and  thus  cause  them  to  rise 
to  the  vibratory  pitch  of  pain. 

We  know  that  the  absence  of  repose  for  the  brain, 
prolonged  vigils,  uninterrupted  intellectual  work,  moral 
emotions,  engender  a  local  heating  of  the  cerebral  sub- 
stance, cephalalgia,  and  aching  of  the  brain.  The  calling 
into  activity  of  the  cerebral  cell,  in  an  extra-physiological 
manner,  at  the  same  time  abnormally  develops  its  histo- 
logical sensibility,  and  induces,  as  a  necessary  conse- 
quence, prolonged  erethism  and  pain,  in  the  manner  we 
have  just  pointed  out. 

We  all  know  by  experience,  how  painfully  a  piece 
of  taskwork  which  does  not  provoke  an  intellectual 
appetite,  is  done — it  is  an  effort  which  the  brain  makes 
against  the  grain  ;  and  how,  on  the  contrary,  when  the 

•  Sec  p.  'j'j,  "  Experiments  of  Schiff.' 


PERTURBATIONS   OF   SENSIBILITY.  II9 

task  is  a  pleasant  one,  there  is  a  fascination  in  setting 
to  work,  and  a  rapidity  in  the  execution.  The  natural 
spontaneity  of  the  brain  thus  supplies  the  place  of  effort. 

All  those  who  have  suffered  from  headache  know  how 
exquisite  is  the  sensibility  of  all  regions  of  the  sensoriitm  ; 
how  painful  a  thrill  is  produced  by  the  least  noise  from 
without,  the  slightest  shock  of  the  thoughts  which  tra- 
verse the  brain.  They  know  also  that  silence,  and  sleep 
— that  is  to  say  the  cessation  of  every  source  of  cerebral 
excitement — are  the  only  efficacious  means  for  charming 
away  these  painful  crises  through  which  the  sensibility 
of  the  sensorium  has  to  pass.* 

More  than  this,  a  comparative  examination  of  the 
manner  in  which  the  central  and  peripheral  regions  of 
the  nervous  system  behave  in  presence  of  anaesthetic 
agents,  shows  us  a  new  connection  between  the  modes  in 
which  sensibility  is  developed  in  these  two  opposite 
regions. 

Thus,  when  hyperaesthesia  appears  in  the  sensorium, 
when  the  pain  reveals  itself  either  as  the  effect  of  too 
intense  peripheral  excitement  (a  wound,  or  any  injury 
of  the  surface  of  the  body),  or  as  the  effect  of  a  per- 
sistent irritation  (moral  emotion,  prolonged  intellectual 
labour,  etc.),  we  may  artificially  cause  the  level  of  pain- 
ful over-excitement  to  fall  several  degrees,  just  as  if  we 
had   to  deal  with  a  peripheral  plexus  in  a  condition  of 

•  Just  as  we  have  seen  before,  with  regrird  to  the  peripheral  regions,  that 
pain  was  only  the  e  pression  of  the  sensibihty  of  Hvini(  tissues  in  exercise  ; 
so  for  the  central  regions  pain  is  only  possible  in  proportion  to  their  soundness. 
The  slow  destruction  of  the  sensorium  by  chronic  disorganizations,  progressively 
leads  to  the  cessation  of  certain  forms  of  cephalalgia.  Thus  we  find  paralytics 
who  at  the  beginning  of  their  disease  have  had  very  severe  headaches,  end  by 
no  longer  suffering  from  any  painful  symptom. 


120  THE   BRAIN   AND   ITS   FUNCTIONS. 

painful  erethism,  and  may  thus  to  a  certain  extent  dull 
the  painful  vibrations.  It  is  thus  that  anaesthetics  and 
stupefying  drugs  act  when  introduced  as  inhalations. 

In  operations  on  patients  under  chloroform,  this 
agent  spreading  through  the  plexuses  of  the  scnsorimn 
freezes  its  nervous  elements,  which  it  steeps  in  the 
same  anaesthesia  in  which  the  sensitive  plexuses  of  the 
skin  of  a  hysterical  patient  remain.* 

Painful  excitations  are  in  vain  launched  from  the 
peripheral  regions  in  the  form  of  keen  incisive  thrills, 
when  the  tissues  are  cut ;  they  meet  in  the  sensoriinn 
only  zones  of  cells  physically  modified^  stricken  with 
anaesthesia,  and  incapable  of  erection,  of  feelings  or  of 
being  raised  to  the  pitch  of  pain. 

To  complete  the  resemblance,  just  as  we  see  anal- 
resic  patients  whose  skin  is  pinched,  and  into  whose 
tissues  needles  are  thrust  with  impunity,  witness  with 
indifference  and  without  painful  reaction  what  takes 
place  in  their  bodies  ;  so  we  meet  with  a  certain  num- 
ber of  operation  patients  who,  being  capable  of  analy- 
zing their  sensations  at  the  moment  of  operation,  tell 
us  that  during  the  period  of  anaesthesia  into  which  they 
were  plunged,  they  have  felt  the  cold  of  the  knife 
penetrating   into    their  flesh — that  they   have    felt  the 

*  To  understand  the  mere  mechanism  of  aocesthesia,  it  should  be  known 
that  chloroform  does  not  act  simply  upon  the  nervous  elements.  If  we  place  a 
muscle  in  the  vapours  of  ether  and  chloroform,  or  inject  into  a  limb  a  weak 
solution  of  chloroform  or  ether,  we  induce  rigidity  of  the  muscle  ;  and  when  we 
e  amine  the  change  produced,  we  perceive  that  the  contents  of  the  muscuiar 
libre  are  no  longer  transparent,  but  have  undergone  coagulation.  It  is  to  be 
supposed  that  something  analogous  takes  place  in  the  nerve  cell,  but  this  is 
much  more  delicate,  much  more  sensitive  to  the  action  of  chloroform,  it  being 
first  to  undergo  coagulation.  As  the  chloroform  is  carried  off  by  the  blood, 
the  cell  recovers  from  its  aniesthesia  and  returns  to  its  normal  condition,  as  the 
muscle  cx:overs  from  its  rigidity. 


PERTURBATIONS   OF   SENSIBILITY.  121 

keen  instrument  cutting  through  their  tissues,  but  that 
to  their  surprise  they  perceived  that  they  did  not 
suffer,  and  that  the  usual  pain  was  not  naturally 
disengaged  as  they  would  have  expected.  One  of 
them  told  me  that  he  experienced  a  surprise  simi- 
lar to  that  of  a  person  who  should  plunge  his  hand 
into  a  burning  brazier,  and  should  naturally  be  aston- 
ished at  not  feeling  the  burn. 

Moral  Pain. — Moral  pain  is  only  the  expression  of 
the  moral  sensibility  carried  to  its  maximum  of  inten- 
sity, as  physical  pain  is  but  the  most  exquisite  form  of 
the  physical  sensibility  thrown  into  agitation.  The 
conditions  of  evolution  are  the  same  in.  both  cases, 
except  that  moral  pain  presents  itself  to  us  under 
special  aspects  of  amplitude  and  intensity,  which  give 
it  an  expression  of  a  persistence  quite  characteristic. 

Thus  in  studying  the  etiological  conditions  of  moral 
sensibility,  we  have  seen  how  this  sensibility  was  but  a 
long  synthesis  and  the  resultant  of  a  combination  of  the 
sensibility  of  the  sensorium  thrown  into  agitation  with 
the  involuntary  revival  of  memories,  and  the  incessant 
participation  of  intellectual  activity,  which  always  under- 
lies its  manifestations. 

External  excitations,  as  we  have  already  remarked, 
once  deposited  in  the  sensormiHj  do  not  become 
extinct  all  at  once.  They  survive,  and  like  phospho- 
rescent gleams,  leave  persistent  traces  of  their  passage 
in  the  nervous  plexuses.  On  the  other  hand,  the  ex- 
citations of  intellectual  activity  are  also  concerned  in 
the  process.  They  are  always  alert,  always  active,  and 
by  virtue  of  their  automatic  energies  they  reveal  them- 
selves in   the  shape  of  ideas  associated   with  contem- 

lO 


122  THE  BRAIN   AND   ITS  FUNCTIONS. 

porary  reminiscences  and  connected  reflections ;  so 
that  they  also  constitute,  as  it  were,  so  many  foci  of 
activity  capable  of  incessantly  intensifying  the  move- 
ment in  the  plexuses  of  the  sensorium. 

The  result,  as  regards  the  genealogy  of  moral  pain, 
of  the  double  participation  of  these  two  physiolo- 
gical factors — the  persistence  of  impressions,  and  the 
incessant  participation  of  the  intellect  in  the  phenomena 
of  sensibility,  is  this,  that  when  the  plexuses  of  our 
sensoriurn  have  been  thus  thrilled  vividly  to  their  depths, 
the  impression  so  produced  does  not  immediately 
die  away.  It  becomes  persistent — lives  upon  memo- 
ries, and  vibrates  like  the  dolorous  echo  of  a  former 
agitation  of  our  sensibility,  to  be  effaced  only  as  this 
sensibility  becomes  dulled  in  the  region  where  it  was 
primarily  engendered.  The  shock  once  produced,  it 
becomes  incarnate,  and  perpetuates  itself  in  us  by  pro- 
ducing the  phenomena  of  moral  grief  We  cannot 
avoid  feeling  it,  and  suffering — each  in  his  own  manner 
it  is  true,  each  in  a  different  degree,  according  to  the 
delicacy  or  richness  of  the  nervous  elements  which 
constitute  his  sensoriurn.  It  is  no  more  possible  to 
escape  from  a  painful  emotion  which  comes  to  inflict 
a  sort  of  contusion  upon  our  natural  sensibility,  than  to 
escape  an  ecchymosis  when  a  heavy  body  crushes  our 
integuments. 

On  the  other  hand,  this  participation  of  the  intellect 
in  all  that  concerns  us,  and  all  that  moves  us,  naturally 
becomes  a  species  of  incessant  morbid  excitement  of 
our  moral  erethism,  and  perpetuates  the  griefs  of  the 
sensitive  regions  of  our  being.  The  physiological  excit- 
ations which  stir   up  and  vivify  our  moral   sensibility 


PERTURBATIONS   OF   SENSIBILITY.  1 23 

are,   then,  also  those  which  vivify  and  perpetuate  our 
moral  pains. 

It  is  because  man  can  judge  of  the  loss  which  he 
undergoes  in  consequence  of  the  sudden  ruin  of  his 
affections  and  dearest  hopes  ;  because  he  can  estimate 
the  happy  memories  which  are  fleeting;  the  bygone  joys, 
the  sorrows  of  the  future,  and  the  griefs  of  the  present  ; 
because  he  finds  before  his  mind's  eye  a  multitude  of 
elements  furnished  by  his  intellectual  activity  working 
automatically — that  he  suffers  morally  in  his  sentient 
being,  and  that  the  w-ounds  of  his  heart,  incessantly 
revived  by  a  crowd  of  memories  which  assail  it  like  so 
many  morbid  stimulations  automatically  arising,  remain 
always  open ;  that  pain  lives  within  him  and  preys  upon 
him  perpetually. 

Vuinus  alit  venis  et  coeco  carpitur  igni. 

Thus  it  is  that  when  trouble  attacks  him  he  passes 
through  that  series  of  dolorous  stages  which  lead  him 
to  slow  despair,  to  that  phase  of  profound  despondency 
so  often  the  road  to  mental  maladies. 

The  m.oral  life  of  an  individual,  his  stock  of  natural 
sensibility  and  emotivity,  is  therefore  kept  in  a  con- 
dition of  freshness  and  integrity  only  by  the  incessant 
activity  of  his  memory,  and  intelligence,  and  the  con- 
scious perception  of  the  things  of  the  external  world. 

When  the  memor}^  and  intelligence  begin  to  fail,  and 
the  energy  of  the  mind  to  grow  weak,  the  decadence  of 
the  moral  sensibility  follows  that  of  the  intelligence 
step  by  step.  In  a  man  intellectually  degraded  w^e  can 
only  count  upon  a  low  morality.  And  this  is  so  true, 
that    a    perLon    w^hose    intellectual    powers    have   been 


124  THE  BRAIN   AND  ITS   FUNCTIONS. 

already  impaired,  either  by  the  occurrence  of  diffuse 
cerebral  congestions  or  by  alcoholic  excesses  which 
have  impaired  the  very  substance  of  his  sensorium,  no 
longer  feels  moral  pain  according  to  the  regular  pro- 
cesses by  which  it  is  developed  in  his  fellow  men.  The 
student  of  mental  maladies  frequently  meets  with  indi- 
viduals apparently  reasoning  with  inflexible  logic,  and 
preserving  a  certain  energy  of  the  intellectual  faculties, 
yet  no  longer  having  any  exact  notion  of  what  is  pass- 
ing around  them,  or  capable  of  comprehending,  like 
every  one  else,  the  emotions  of  moral  sensibility.  If 
we  try  to  convey  to  them  a  family  trouble,  or  the  loss 
of  one  formerly  loved  ;  if  we  seek  to  set  some  chord 
of  emotion  vibrating  within  them,  nothing  moves  them. 
They  remain  impassive,  and  this  defect  of  moral*  reac- 
tion indicates  at  once  their  dullness  of  comprehension, 
and  the  silence  of  the  intellectual  activity  which  has  not 
normally  interpreted  the  sense  of  the  words  and  their 
range  of  significance.  In  this  defect  of  sensitive  reac- 
tion, we  have  a  criterion  which  indicates  to  the  observer 
the  secret  dilapidations  which  have  occurred  in  the 
sphere  of  mental  activity. 

To  sum  up,  it  is  in  this  special  mode  of  evolution  of 
the  moral  sensibility, in  its  dependence  upon  both  ancient 
memories  and  intellectual  activity,  that  we  must  look 
for  the  secret  of  the  strong  action  of  moral  influences 
upon  the  development  of  diseases  of  the  brain. 

It  is  because  man  is  sensitive  that  he  suffers,  and 
because  he  is,  as  an  individual,  sensitive  in  a  certain 
manner,  and  in  certain  favourite  directions — because  he 
is  more  or  less  interested  in  the  acts  of  his  life,  and 
conscious  of  what   passes   around  him,  that  he  suffers 


PERTURBATIONS   OF   SENSIBILITY.  12$ 

morally.  The  moral  wound  which  is  established  in  him, 
once  produced,  does  not  heal  up  all  at  once,  it  extends 
its  influence,  festers  like  a  serpiginous  ulcer,  and  being 
incessantly  irritated  by  automatic  impressions  radiating 
from  the  sphere  of  the  intellect,  perpetuates  itself,  always 
poignant,  in  the  sensormm^  reviving  in  a  thousand  forms 
on  the  smallest  provocation.  It  thus  becomes,  by 
reason  of  the  special  conditions  of  the  medium  into 
which  it  has  eaten,  a  cause  of  ruin,  of  progressive  wear- 
ing out  of  the  mental  energies,  unless  a  profound  diver- 
sion be  immediately  created,  or  a  salutary  method  of 
treatment  intervene  to  arrest  disorders  which  tend  to 
become  incurable. 


CHAPTER  V. 

DEVELOPMENT   OF   SENSIBILITY. 

Sensibility  in  living  beings  awakens  with  life.  As 
regards  histological  sensibility  proper,  it  is  inherent  in 
the  primordial  phenomena  of  the  evolution  of  the  embry- 
onic cells  ;  it  is  a  hereditary  legacy  which  accumulates 
incessantly,  by  the  addition  of  new  elements,  and  new 
tissues,  in  proportion  as  the  organism  completes  and 
perfects  itself. 

It  is  by  virtue  of  the  individual  sensibility  of  the  em- 
bryonic cells  that  these  borrow  from  the  surrounding 
medium,  the  fluid  atmosphere  which  bathes  them,  the 
elements  suitable  for  their  special  nutrition,  and  that 
the  nervous  system  itself  appears  as  an  apparatus  of 
centralization  and  organic  perfectionment. 

In  the  first  phases  of  foetal  life  it  is  very  difficult  to 
fix  definitely  at  what  epoch  sensibility  manifests  itself  as 
a  motor  force  ;  nevertheless,  from  the  fourth  month  we 
can  observe  that  the  nervous  system  begins  to  react  and 
to  reveal  the  vitality  of  the  diff'erent  apparatuses  of 
which  it  is  made  up. 

We  know,  indeed,  that  from  this  period  the  foetjs  is 
sensitive  to  the  action  of  cold,  and  that  we  can  develop 
its  spontaneous  movements  by  applying  a  cold  hand  to  the 
abdomen  of  the  mother.     We  know  also  that  it  executes 


DEVELOPMENT  OF   SENSIBILITY.  12/ 

spontaneous  movements  to  withdraw  from  pressure 
that  constrains  it  and  brings  its  sensibihty  into  play. 

We  may  then  legitimately  conclude  that  here  we  have 
the  first  gleams  of  awakening  sensibility,  which  from 
this  period  is  transmitted  through  its  natural  channels 
by  the  nervous  system,  and  already  regulated  in  the 
manner  in  which  it  will  subsequently  manifest  itself 
throughout  the  organism. 

At  birth  it  is  the  entire  cutaneous  sensibility,  suddenly 
awakened  by  the  irruption  of  the  young  being  into  a 
cold  atmosphere,  which  determines  its  first  startled  cries, 
and  its  first  inspirations.  It  is,  then,  in  the  sensitive 
peripheral  regions  that  the  first  sparks  which  are  to 
develop  the  play  of  the  organic  machinery,  and  those 
excitations  of  the  vital  knot  which  once  set  in  motion 
will  only  cease  at  the  end  of  life,  have  their  origin. 

From  this  time  forth  the  child  takes  the  breast  of  the 
nurse  automatically,  and  by  virtue  of  hereditary  vital 
forces  which  already  exist  in  a  latent  state  in  his  nervous 
system.  His  organic  appetites  are  gratified  by  the  milk 
he  sucks,  and  he  feeds  himself  organically,  like  an  organic 
cell,  which  borrows  from  the  surrounding  medium  the 
materials  which  suit  it.  But  at  the  same  time  he  ex- 
presses the  satisfaction  he  feels  in  his  own  manner  ;  he 
smiles  on  seeing  the  breast  which  yields  him  his  nourish- 
ment and  life,  and  from  that  time  his  natural  sensibility 
is  thrown  into  agitation,  his  sensorium  is  affected.  He 
rejoices  because  he  remembers,  because  he  has  retained 
a  memory  of  the  satisfaction  of  his  physical  appetites. 

Here,  in  these  first  phases  of  the  manifestations  of 
human  sensibility,  is  the  rudimentary  formula  according 
to  which  the  moral  sensibility  of  the  human  being  shall 


128  THE  BRAIN  AND   ITS  FUNCTIONS. 

henceforth  be  evolved  In  the  course  of  his  Hfe,  and  already 
such  as  we  have  found  it  in  the  adult — that  is  to  say, 
reducible  to  a  purely  sensitive  phenomenon  multiplied 
by  the  intervention  of  memory  and  intelligence. 

From  these  first  moments  onwards  sensibility  develops 
rapidly. 

The  different  sensorial  foci  by  the  aid  of  which  it 
comes  to  life,  light  up,  multiply,  and  successively  attain  to 
perfection.  The  child  successively  learns  to  see,  hear, 
feel,  smell,  and  taste.  He  remembers  satisfactions  re- 
ceived. He  recognizes  the  persons  who  immediately 
surround  him  and  load  him  with  caresses.  It  was  the 
sight  of  the  bosom  of  his  nurse  which  in  the  first  instance 
excited  his  first  smiles,  and  as  his  field  of  vision  extends, 
it  is  the  entire  person  of  his  nurse  to  which  these  same 
smiles  appeal ;  then,  as  it  extends  still  further,  he  re- 
cognizes those  whom  he  frequently  sees,  and  who  present 
a  pleasant  physiognomy  to  him. 

Soon,  by  the  progressive  unfolding  of  all  the  latent 
activities  of  the  organic  elements  which  come  into  exist- 
ence, the  general  life  of  the  child  develops  in  ample 
luxuriance. 

Moral  sensibility  undergoes  the  same  developmental 
movement ;  intelligence  and  memory  enrich  these  first 
manifestations  every  instant. 

Henceforward  the  first  links  of  family  affection 
bind  themselves  round  his  heart,  and  thus  become 
the  origin  of  his  first  sentiments  and  emotions.  He 
loves  those  who  approach  him,  for  the  sake  of  the 
good  things  they  have  already  done  for  him.  He 
can  recognize  those  who  wish  him  well  or  ill, 
or   who    are    simply    indifferent    to    him  ;    and    thus 


DEVELOPMENT   OF   SENSIBILITY.-  1 29 

ft  is  that  to  every  one  who  comes  in  contact  with  him, 
and  excites  his  sensibility  in  one  way  or  another,  he 
devotes  an  appropriate  memory  and  a  gratitude  propor- 
tioned to  the  good  or  evil  influence  he  has  received. 
He  loves  his  parents,  in  the  first  place,  because  they 
contribute  more  or  less  to  his  well-being  and  his  plea- 
sures, and  because  he  is  in  the  habit  of  seeing  them 
every  day  ;  and  this  incessant  renewal  of  physical  im- 
pressions keeps  the  sentiment  of  gratitude  in  a  condition 
of  permanence  and  freshness  in  his  sensormm.  Those 
who  are  always  present  before  his  eyes  are  similarly 
present  in  his  heart. 

At  another  period  of  human  existence,  the  most 
violent  of  the  sentiments  which  are  calculated  to  set  all 
the  sensitive  chords  of  the  living  being  vibrating — love 
— develops  itself  merely  by  virtue  of  the  same  physio- 
logical laws. 

It  is  at  its  outset,  as  in  the  young  child,  the  satisfac- 
tion of  physical  sensibility  which  forms  the  necessary 
prelude  to  it,  its  first  stage  and  indispensable  condition. 

It  is  because  he  has  been  thrilled  in  all  the  elements 
of  his  physical  sensibility  that  the  living  creature,  at  the 
period  of  love,  is  inevitably  hurried  forward,  by  invin- 
cible hereditary  impulses,  towards  the  being  destined  to 
be  his  complement  and  to  become  the  physiological 
receptacle  of  his  deepest  joys. 

It  is  because  he  has  been  charmed  at  once,  in  all  the 
sensitive  elements  of  his  being,  by  the  sight  of  the 
plastic  beauties  of  the  object  of  his  desires,  by  the 
seductions  of  her  speech,  her  voluptuous  contact,  and 
all  her  intellectual  and  moral  wealth,  that  he  is  cap- 
tivated  and    subdued.      It  is  because  all  his   physical 


130  THE   BRAIN   AND   ITS   FUNCTIONS. 

sensibilities  have  been  simultaneously  awakened,  and 
that  a  period  of  generalized  erethism  is  developed  in 
his  seitsorium,  that  he  loves  the  object  who  has  been  for 
him  the  origin  of  all  his  happiness — that  he  attaches 
himself  to  her,  becomes  her  slave,  and  surrenders  him- 
self altogether ;  just  as,  when  he  was  a  child,  he  loved, 
according  to  the  measure  of  affection  of  which  he  was 
capable,  the  nurse  who  gratified  his  first  sensuous 
appetites. 

Thus  it  is  that  love,  the  concrete  expression  of  all 
the  sensibilities  thrown  into  agitation,  develops  itself  in 
the  living  being  as  a  recognition  of  physical  pleasures 
satisfied,  and  as  a  hope  of  their  repetition  ;  and  that 
this  sentiment,  so  simple  in  rudimentary  organisms,  in 
which  sensibility  is  little  developed,  becomes  compli- 
cated in  the  animal  series  in  proportion  as  the  sum  of 
the  sensitive  elements  multiplies,  and  the  phenomena 
of  moral  sensibility  come  more  into  play. 

In  fact,  in  proportion  as  we  pursue  the  study  of  this 
sentiment  through  the  series  of  living  creatures,  we  see 
that,  by  slow  gradations,  it  undergoes  a  progressive 
transformation,  and  that  in  proportion  as  the  moral 
influences  of  civilization  become  paramount,  the  purely 
animal  physical  love  of  savage  peoples  loses  its  primi- 
tive character,  to  become  clothed  in  new  forms,  appro- 
priate to  the  new  medium  in  which  it  is  developed. 

Thus  it  is  that  polygamy,  which  is  the  social  expres- 
sion of  the  satisfaction  of  all  physical  pleasures,  insen- 
sibly gives  place  to  monogamy,  the  most  perfect 
expression  of  the  union  of  the  man  and  woman,  and 
a  more  serious  guarantee  for  the  maintenance  of  the 
family.     This  regular  form  of  love,  which  is  an  epitome 


DEVELOPMENT   OF   SENSIBILITY.  I3I 

of  the  most  delicate  perfections  of  human  sensibility, 
concentrates  upon  a  single  head  the  sorrows  and  joys 
of  the  past  and  the  hopes  of  the  future,  and  thus 
cements  the  permanent  ties  consecrated  by  the  customs 
of  common  life.  It  inevitably  engenders,  in  every 
degree  of  the  social  scale,  spite  of  the  numerous  short- 
comings by  which  it  is  dishonoured,  those  natural  acts 
of  devotion  and  self-abnegation  for  the  common  work  of 
progeniture,  and  that  whole  series  of  respectable  senti- 
ments of  which  the  domestic  morality  of  monogamous 
peoples  offers  most  striking  examples. 

As  a  man  advances  in  life,  his  sensibility  becomes 
gradually  lessened — the  senses  become  dull,  the  sight 
loses  its  sharpness,  the  skin  its  impressionability  by  ex- 
ternal agents.*  A  sort  of  general  slackening  of  all  his 
functions  impends  over  the  livmg  creature  thus  arrived 
at  the  retrogade  phases  of  his  evolution. 

This  condition  of  diminution  of  the  peripheral  sensi- 
bility is  reflected  in  a  similar  manner  upon  the  sensibility 
of  the  central  regions.  Moral  impressionability  and 
emoti\  ity  lose  their  energy  as  a  man  grows  old.  He  is 
less  and  less  interested  in  external  things  capable  of 
exciting  his  mental  activity.  He  is  less  sensitive,  less 
impressionable,  less  curious  as  to  knowledge  and  feeling, 
and  at  the  same  time  his  intellectual  faculties  are 
simultaneously  impaired.  Memories  of  the  past,  like 
enfeebled  phosphoric  gleams,  persist  for  a  certain  time, 
to  the  exclusion  of  more  recent   remembrances,  but,  in 

*  In  old  persons  the  skin  atrophies  very  remarkably,  and  in  a  great  number 
the  skin  of  the  derma  is  so  attenuated,  that  by  pinchmg  up  a  fold  in  the  dorsal 
region  of  the  hands  I  have  often  been  able  to  observe  that  it  has  become  so 
thin  and  translucent  that  the  circulation  in  the  subcutaneous  capillary  plexuses 
alight  be  seen,  as  in  the  foot  of  a  frog. 


132  THE  BRAIN   AND   ITS  FUNCTIONS. 

the  end.  even  they  too  are  extinguished,  so  that,  the 
circle  of  bygone  things  narrowing  by  degrees,  the  indi- 
vidual feeds  his  sensorhim  only  with  the  current  opera- 
tions of  life.  Material  life  with  all  its  necessities — 
eating,  drinking,  and  sleeping,  becomes,  little  by  little, 
the  favourite  occupation  of  organisms  in  the  period  of 
decadence ;  and  as  to  moral  sensibility,  the  old  man,  an 
egotist  with  few  exceptions,  is  reduced  to  vegetative  life, 
and  becomes  once  more  a  child,  caring  no  longer  for 
those  who  care  for  him  day  after  day.  He  forgets  his 
old  friends,  and  the  most  natural  family  affections,  for 
the  sake  of  the  newest  comer,  and  succumbing  more 
and  more  to  the  interested  demands  of  his  personality, 
he  arrives,  as  regards  moral  sensibility,  at  a  true  anaes- 
thesia which  reflects  the  languishing  condition  of  the 
elements  of  his  nervous  activity. 


BOOK    II. 

ORGANIC    PHOSFHORESCENCE    OF    THE    NERVOUS 

ELEMENTS. 


CHAPTER    I. 

INTRODUCTORY. 

I  HAVE  proposed  to  apply  the  term  phospJiorescencc  to 
that  curious  property  the  nervous  elements  possess,  of 
remaining  for  a  longer  or  shorter  time  in  the  state  of 
vibration  into  which  they  have  been  thrown  by  the 
arrival  of  external  excitations — as  we  see  phosphore- 
scent substances  illuminated  by  solar  rays  continue  to 
shine  after  the  source  of  light  which  has  illuminated 
them  has  disappeared. 

We  know,  indeed,  now,  thanks  to  the  works  of 
modern  physicists,  that  the  vibrations  of  the  ether,  in 
the  form  of  luminous  undulations,  are  capable  of  being 
prolonged  by  phosphorescent  bodies  for  a  longer  or 
shorter  time,  and  thus  surviving  the  cause  which  has 
produced  them. 

Niepce  de  Saint-Victor,  in  his  researches  on  the  dy- 
namic properties  of  light,  has  arrived  at  results  much 
more   precise    and    unexpected ;    since,   in  a    series  of 


134  THE  BRAIN  AND   ITS   FUNCTIONS. 

reports,*  he  has  shown  that  luminous  vibrations  may  be 
to  some  extent  garnered  up  in  a  sheet  of  paper,  and 
remain  as  silent  vibrations  for  a  longer  or  shorter 
period,  ready  to  appear  at  the  call  of  a  revealing  sub- 
stance. Tnus,  having  kept  in  darkness  some  prints  pre- 
viously exposed  to  the  solar  rays,  he,  several  months 
after  this  insulation,  succeeded  in  demonstrating,  by 
means  of  special  reagents,  persistent  traces  of  the 
photographic  action  of  the  sun  upon  their  surface. 

On  the  other  hand,  the  daily  practice  of  photo- 
graphic reproduction  by  means  of  dry  collodion,  is  an 
irrefragable  demonstration  of  the  aptitude  which  certain 
substances  gifted  with  special  elective  sensibility  have 
for  preserving  persistent  traces  of  the  luminous  vibra- 
tions that  have  for  a  certain  time  affected  them.*  In 
fact,  when  we  expose  a  plate  of  dry  collodion  to  the 
luminous  rays,  and  several  weeks  after  such  exposure 
develop  the  latent  image  it  contains,  we  produce  a  resur- 
rection of  the  persistent  vibrations  and  obtain  a  record 
of  the  absent  sun  ;  and  this  is  so  true,  in  this  case  of 
persistence  of  a  vibratory  movement  which  has  but  a 
limited  duration  within  which  it  must  be  seized,  that 
if  we  pass  the  prescribed  limits  and  wait  too  long,  the 
movement  gradually  becomes  enfeebled,  like  a  source 
of  heat  which  cools  and  ceases  to  be  able  to  reveal  its 
existence. 

This  curious  property,  which  inorganic  substances 
possess,  of  preserving  for  a  longer  or  shorter  period  a 
species  of  prolongation  of  the  impressions  which  have 
first  set  them   in  motion,  is  found  once  more  under  new 

*  "Comptes  rendus  de  I'Academie  des  Sciences,"  Nov.  i6th  1857,  vol.  xlv. 
p.  811,  and  Mc»rch  ist,  1858,  vol.  xlvi.  p.  448. 


PHOSPHORESCENCE  OF  THE  NERVOUS  ELEMENTS.    1 35 

forms,  with  special  phenomena,  it  is  true,  but  essentially 
the  same,  when  we  come  to  study  the  dynamic  pheno- 
mena of  the  life  of  the  nervous  elements. 

These  also  are  gifted  with  a  sort  of  organic  phospho- 
rescence, and  are  capable  of  vibrating  and  storing  up 
external  impressions,  of  remaining  for  a  certain  time  in 
a  sort  of  transient  catalepsy,  in  the  vibratory  state  into 
which  they  have  been  incidentally  thrown,  and  of  causing 
the  first  impressions  to  revive  after  the  lapse  of  time. 

We  all,  indeed,  know  that  the  cells  of  the  retina  con- 
tinue in  a  state  of  vibration  after  an  excitation  has 
ceased.  It  has  been  calculated  by  Platau  that  this  per- 
sistence of  impressions  may  be  estimated  at  from  thirty- 
two  to  thirty-five  seconds.*  To  this  persistence  of 
vibrations,  and  that  special  retentive  force  which  the 
nervous  elements  possess,  is  due  the  fact  that  two  suc- 
cessive and  rapid  impressions  become  confounded,  and 
thus  give  a  continuous  impression  :  that  a  live  coal 
whirled  round  at  the  end  of  a  string  gives  the  impres- 
sion of  a  circle  of  fire  :  that  a  disc,  painted  with  the 
colours  of  the  spectrum,  when  in  rotation  gives  only 
the  sensation  of  white  light,  because  all  its  colours  are 
confounded  and  form  for  us  an  unique  resultant,  which 
is  the  idea  of  white.  All  those  who  occupy  themselves 
with  histology  know  that  after  prolonged  work  the 
images  seen  in  the  focus  of  the  microscope  live  in  the 
fundus  of  the  eye,  and  that  sometimes,   after  several 

*  The  duration  of  impressions  upon  the  retina  is  much  longer  than  that  of 
the  action  of  Uglit.  According  to  Platau,  the  duration  of  the  consecutive 
impression  increases  in  the  direct  ratio  of  that  of  the  primary  impression  (Pin  the 
direct  ratio  of  its  intensity).  Thus  the  consecutive  image  of  a  strongly  illu- 
minated body  may  be  kept  in  the  eye  for  a  very  long  time.  (MuUer,  "  Piiysio- 
ogie,'   vol.  ii.  p.  355.) 


136  THE  BRAIN  AND  ITS  FUNCTIONS. 

hours'  work,  shutting  one's  eyes  is  sufficient  to  cause 
them  to  reappear  with  great  distinctness. 

It  is  the  same  with  auditory  impressions.  The  audi- 
tory nerves  preserve  for  a  long  time  the  trace  of  im- 
pressions which  have  set  them  vibrating.  After  a  rail- 
way journey,  we  hear,  for  several  hours  after  arrival,  the 
noise  of  the  rattling  of  the  carriage.  A  musical  air, 
and  certain  favourite  refrains,  involuntarily  resound  in 
one's  ears,  and  that  often  in  a  most  disagreeable  manner. 

After  long  musical  seances^  says  Dr.  Moos  (of  Heidel- 
berg), the  sounds  persisted  for  fifteen  days  in  one 
patient,  and  in  another,  a  professor  of  music,  for  several 
hours  after  each  lesson.* 

The  gustatory  plexuses  also  seem  capable  of  thus 
preserving  the  trace  of  agreeable  or  disagreeable  im- 
pressions which  have  affected  them,  and  the  intensity 
of  the  impression  is  sometimes  lively  enough  to  pro- 
duce, retrospectively,  either  a  secretion  of  saliva  when 
the  mouth  waters  at  the  thought  of  something  nice,  or, 
in  other  circumstances,  a  sensation  of  nausea  when  the 
substance  has  produced  an  unpleasant  sensation. 

The  impressions  of  general  sensibility,  olfactory  sen- 
sibility, etc.,  appear  to  present  analogous  phenomena. 

This  species  of  histological  catalepsy,  which  to  some 
extent  polarises  the  nerve-cells  in  the  situations  in  which 
they  have  been  immediately  placed  at  the  time  of  their 
first  impression,  is  not  merely  a  unique  phenomenon, 
which  is  met  with  in  the  peripheral  regions  of  the 
nervous  system  ;  it  is  also  met  with  still  more  fully 
developed  in  the  central  regions  of  the  system,  where 
it  appears  with  such  pronounced  and  fixed  characters 

*  *' Annales  Mcdico-psychol.,"  vol.  ii.  p.  121,  1869. 


PilOSPIIORESCENCE  OF  THE  NERVOUS  ELEMENTS.    I37 

that  we  might  say  that  it  governs  the  manifestations  of 
automatic  hfe  in  the  spinal  cord,  and  directs  those  of 
psycho-intellectual  activity  in  the  brain. 

In  the  different  segments  of  the  spinal  cord  the  per- 
sistence of  impressions  reveals  itself  very  evidently  in 
the  accomplishment  of  all  those  co-ordinated  move- 
ments which,  not  being  a  part  of  the  hereditary  patri- 
mony of  the  motor  apparatuses  of  the  organism,  are 
therefore  acquired  by  habit,  being  the  direct  product  of 
education. 

We  know  that  the  greater  number  of  the  rhythmic 
movements  we  execute  in  most  bodily  exercises — 
dancing,  fencing,  playing  on  musical  instruments — are 
methodical  movements  which  we  never  accomplish 
(except  the  first  time)  by  the  intervention  of  the  will  ; 
that  they  are  the  effect  of  long  apprenticeship  ;  that 
they  are  only  acquired  by  exercise,  the  force  of  habit, 
and  the  imitative  tendency  we  have,  to  reproduce 
patterns  presented  to  us.  Now,  our  muscles  can  move 
in  such  marvellous  union  according  to  given  indications 
— our  movements  can  be  harmoniously  combined  in 
accordance  with  the  operations  to  be  accomplished, 
only  by  virtue  of'  the  latent  aptitude  of  the  excito- 
motor  cells  of  the  spinal  cord  for  preserving  records  of 
the  impressions  that  have  first  thrown  them  into  agita- 
tion— for  remaining  for  a  longer  or  shorter  time  in  the 
primordial  condition  first  imposed  upon  them. 

It  is,  then,  our  first  impressions  that  vibrate  in  us  like 
distant  echoes  of  the  past,  and  serve  as  a  stimulus  to 
the  excitations  of  automatic  life.  It  is  they  that,  always 
alive,  always  faithful  to  themselves,  are  incessantly  dis- 
engaged in  the  form  of  imconscions  reminiscences,  regu- 
II 


138  THE  BRAIN   AND   ITS   FUNCTIONS. 

larly  rhythmic    motor   manifestations,  which  faithfully 
reproduce  the  impression  of  the  primordial  excitation. 

It  is  the  same  persistent  excitations,  condensed  in 
the  sphere  of  automatic  activity,  that  in  certain  morbid 
cases,  when  the  regions  of  the  sensormm  and  conscious 
perception  are  temporarily  closed  to  impressions  from 
without,  excite  those  very  curious  harmonic  movements 
accomplished  by  certain  somnambulists,  which  take 
place  inotu  propria,  by  the  simple  calling  into  activity 
of  the  automatic  regions  which  act  of  themselves,  and 
exhibit  externally  a  series  of  tniconscioiLs  reminiscences. 
In  connection  with  this  subject,  Mesnet  has  lately  re- 
ported a  most  interesting  case — that  of  a  soldier,  who, 
having  received  a  shot  in  the  head,  afterwards  suffered 
from  very  strange  symptoms.  • 

This  man  was  subject  to  a  species  of  somnambulistic 
crises,  in  consequence  of  which  his  sensoriimt  was  to  a 
great  extent  cut  off  from  all  external  impressions.  He 
ceased,  more  or  less  suddenly,  to  enter  into  contact 
with  the  surrounding  medium,  and  then,  while  in  this 
condition,  would  walk  about,  go  and  come,  and  if  any- 
one endeavoured  to  direct  his  movements  in  any 
definite  manner,  the  impulse  was  inevitably  developed 
in  the  direction  of  former  excitations  preserved  in  the 
state  of  unconscious  reminiscences  in  the  plexuses  of 
his  automatic  activity. 

Thus,  for  instance,  on  putting  his  walking  stick  into 
his  hand,  the  touch  of  it  reminded  him  of  his  gun,  and 
he  would  then  place  himself  in  a  position  as  though  he 
were  present  at  a  battle.  If  a  pen  were  put  into  his 
hand,  the  precise  movements  necessary  for  tracing 
written  characters  were  unconsciously  produced  in  him. 


riiOSPHORESCENCE  OF  THE  NERVOUS  ELEMENTS.    1 39 

These  motor  excitations  were  automatically  developed  in 
the  store  of  latent  reminiscences  grouped  according  to 
a  primordial  arrangement,  and  producing,  as  it  were, 
phosphorescent  gleams  of  the  past ;  as  we  see  in  decapi- 
tated animals  similar  movements  excited  through  the 
preservation  of  the  automatic  activity  of  the  spinal 
cord.* 

Legrand  du  Saulle  has  reported  a  case  which  is  some- 
what analogous  to  the  preceding.  It  is  that  of  a 
young  somnambulist,  a  ropemaker  by  trade,  who,  if 
seized  with  a  fit  of  somnambulism  when  twisting  his 
rope,  would  continue  the  operation  he  had  begun,  even 
while  asleep.i- 

In  my  own  wards  I  had  a  patient,  still  young,  who 
had  been  for  a  long  time  attached  to  the  Salpetriere, 
as  an  assistant  in  the  linen-room,  being  employed  to 
fold  the  clothes  and  roll  bandages.  In  the  last  years  of 
her  life  this  woman,  completely  blind  and  paraplegic, 
presented  the  following  phenomena.  While  lying  on 
her  back,  if  any  one  put  into  her  hands  an  unrolled 
bandage,  or  even  the  end  of  a  cord,  the  touch  imme- 
diately awoke  in  her  reminiscences  of  her  former  work, 
and  she  began  autpmatically  to  make  a  rolling  motion 
with  her  hands,  without  knowing  what  she  was  doing,  as 
though  she  had  been  a  piece  of  machinery. 

We  may  then  assert  that  the  nervous  plexuses  of  the 
spinal  cord  preserve  in  their  minute  structure  (like  the 
peripheral  nervous  plexuses,  the  retina  among  others) 
records  of  the  impressions  which  have  previously  excited 

*  Mesnet,  "Sur  I'automatisme  de  la  memoire  et  des  souvenirs."  (Union 
Medicale,  1874,  number  87,) 

f  "  Annales  Mddico-psychol.,"  1863,  tome  I.  p.  89.  (Legrand  du  SauDe, 
•*  Le  somnambulisme  natuiel.") 


140  THE  BRAIN  AND   ITS  FUNCTIONS. 

them,  and  that  these  persistent  records  thus  become  like 
a  scries  of  fixed  autogenic  excitations,  designed  to  act 
at  a  long  range,  to  radiate  to  a  distance,  and  thus  to 
produce  a  series  of  reactions  quite  similar  to  those  to 
which  they  at  first  gave  rise.  These  phenomena  of 
motor  reaction,  which  take  place  merely  through  the 
calling  into  play  of  the  organs  of  automatic  life,  are 
capable  of  spontaneous  evolution,  and  of  producing  a 
repetition  of  certain  habitual  movements  without  any 
participation  on  the  part  of  the  conscious  personality, 
which  is  absent  for  the  moment.* 

In  entering  upon  the  study  of  the  cerebral  activity 
proper,  we  shall  see  what  an  important  part  this  pro- 
perty which  the  nervous  elements  possess  of  retaining 
a  record  of  former  impressions,  plays  in  the  operations 
of  the  life  of  the  brain,  and  in  what  varied  forms  this 
organic  phosphorescence,  always  identical  with  itself, 
always  present  and  distributed  throughout  the  nervous 
elements  which  compose  the  tissue  of  the  brain,  per- 
forms its  functions. 

It  is  diffused  throughout  all  the  agglomerations  of 
cells,  which  are  like  so  m^any  active  foci  of  phospho- 
rescence, but  unites  into  a  single  resultant  which  concen- 
trates all  the  sparse  activities  of  the  cerebral  cells.  It 
thus  becomes,  under  the  denomination  of  the  general 
faculty  of  memory,  a  true  synthesis  of  one  of  the 
primordial  properties  of  the  nervous  elements. 

The  elements  of  the  cerebral  substance,  the   uncon- 

*  See  an  account  of  experiments  made  on  the  body  of  a  decapitated  animal, 
hi  connexion  w'nh  the  development  of  manifestations  of  automatic  hfe,  in  a 
direction  determined  by  previous  habit,  and  of  the  persistence  of  certain  move* 
nients  directed  to  a  certain  end.  (Ch.  Robin,  "Journal  dePhysiologie,"  Paris, 
1869,  p.  90.) 


PHOSPHORESCENCE  OF  THE  NERVOUS  ELEMENTS.    I4I 

scious  agents  of  the  manifestations  of  our  psyciio-intel- 
Icctual  life,  work  in  silence  at  the  operations  which 
they  accomplish  in  common.  They  associate  together, 
with  their  manifold  properties,  in  one  harmonious  effort, 
corresponding  with  one  another  by  the  mysterious 
channels  of  their  anastomoses,  and  without  our  know- 
ledge preserve  in  their  minute  organism  posthumous 
prolongations  of  past  impressions.  They  act  simulta- 
neously to  produce  the  phenomena  of  memory,  and 
separately  give  oft'  reminiscences,  as  illuminated  bodies 
give  off  the  luminous  waves  they  have  stored  up  in 
their  substance ;  this  marvellous  power  of  the  cerebral 
cells,  which  depends  on  the  favourable  conditions  in  the 
midst  of  which  they  live,  being  maintained  in  a  con- 
dition of  perpetual  vigour  so  long  as  the  physical  con- 
ditions of  its  material  constitution  are  observed,  and  so 
long  as  it  is  associated  with  the  vital  phenomena  of 
the  organism. 

The  phenomena  of  memory,  thus  looked  at  as  a  neces- 
sary consequence  of  a  fundamental  property  of  the 
nervous  elements,  enter  directly  into  the  mechanism 
of  the  different  regular  processes  of  cerebral  activity. 
They  may  consequently  be  looked  upon  from  the  succes- 
sive points  of  view  of  their  genesis,  their  evolution,  their 
mechanism,  the  diverse  phases  they  pass  through  during 
the  life  of  the  individual,  and  the  functional  disturbances 
from  which  they  are  liable  to  suffer. 


CHAPTER  II. 

GENESIS  AND   EVOLUTION   OF   MEMORY.  , 

In  order  that  the  processes  of  cerebral  activity 
which  constitute  memory  shall  be  evolved  according  to 
their  natural  laws,  it  is  necessary  that  the  peripheral 
regions  of  the  system  which  collect  and  transport  sen- 
sorial impressions,  on  the  one  hand,  and  the  central 
regions  which  transform  and  absorb  them,  on  the  other 
hand,  shall  be  reciprocally  in  suitable  conditions  of 
physiological  conductility  and  receptivity. 

I.  It  is  indeed  in  the  peripheral  regions,  in  the  midst 
of  the  ultimate  nervous  expansions,  that  the  activity  of 
the  central  regions  finds  its  regular  food.  Thence  it  is 
that  all  the  stimulations  destined  to  set  them  in  motion 
proceed. 

When  an  external  excitation  is  reverberated  to  any 
point  whatever  of  their  essential  structure — whether  it  be 
a  sonorous  wave  thrilling  through  the  acoustic  expansions, 
or  a  luminous  wave  becoming  extinguished  in  the  regions 
of  the  retina,  or  any  direct  stimulus  which  sets  in  vibration 
the  sensitive  nerves  of  the  skin  and  mucous  membranes 
— immediately  this  purely  physical  excitation  is  trans- 
formed on  the  spot  by  the  peculiar  action  of  the  nervous 
plexus  in  erethism.  It  absorbs  it,  transforms  it  into 
nervous  vibrations,  and  to  some  extent  animalizes  it  by 
incorporating  it  with  the  organism. 


GENESIS  AND  EVOLUTION   OF   MEMORY.        J43 

Now,  since  the  peripheral  nerve-cells,  as  we  have  said, 
retain  in  themselves,  like  phosphorescent  gleams,  the 
record  of  those  stimulations  which  have  first  set  them 
vibrating,  the  result  is  that  these  persistent  impressions 
become,  without  our  knowledge,  like  a  store  of  latent 
peripheral  reminiscences,  which  hold  the  partner  cells  of 
the  central  regions  in  a  sort  of  persistent  vibratory 
sympathy.  They  in  their  turn  assist  the  action  of  the 
central  memory,  and  thus  become  a  means  of  physio- 
logical reinforcement  designed  to  vivify  and  maintain  its 
activity. 

This  solidarity  between  the  peripheral  and  central 
regions  of  the  system  is  so  real,  that  when  the  former 
fail,  the  functionment  of  the  central  regions  is  at  the 
same  time  interrupted. 

When  the  sensitive  peripheral  regions  are  in  a  state 
of  anaesthesia  central  perception  ceases.  There  is  no 
persistent  reminiscence  in  the  sejisormnty  because  the 
trace  of  the  persistent  peripheral  impression  has  not  been 
registered.  Touch,  pinch,  excite  the  skin  of  a  hysterical 
patient  in  any  way  you  please,  if  the  eyes  be  closed,  she 
will  retain  no  remembrance  whatever  of  the  cutaneous 
excitations,  because  her  peripheral  nervous  plexuses 
being  stupefied,  will  not  have  been  able  to  transmit  to 
the  sensorium  anything  that  has  taken  place  in  their 
internal  structure.  I  have  often  seen  general  paralytics, 
attacked  with  transient  anaesthesia  of  the  gustatory 
and  pharyngeal  nerves,  bitterly  complain  to  me  that 
they  had  not  been  given  a  particular  dish  at  their 
meal,  I  having  been  present  when  they  had  partaken  of 
the  food  which  they  declared  they  had  not  received. 
Then  again,  the  absence  of  sensibility  in  the  peripheral 


144  THE  BRAIN   AND  ITS  FUNCTIONS. 

region  causes  the  sensorial  impression  not  to  be  absorbed 
on  the  spot,  nor  directly  transmitted  to  the  central 
regions  by  its  habitual  channels. 

In  order  that  the  sensorial  impression  shall  produce 
the  desired  effects  in  the  plexuses  of  the  seiisoriiim,  and 
shall  be  clearly  perceived,  it  is  necessary  then  that  the 
peripheral  plexuses,  which  are  its  true  gates  of  admission 
into  the  organism,  shall  be  in  a  condition  of  receptivity 
and  peculiar  erethism,  that  their  natural  sensibiHty  shall 
be  directly  awakened,  and  that  there  shall  be  on  their 
part  an  active  and  prolonged  participation  when  the 
stimulation  from  without  arrives. 

Every  one  knows,  indeed,  that  a  slight  and  fugitive 
impression  leaves  but  insignificant  traces  of  its  passage ; 
that  an  incessant  repetition  of  the  same  impressions 
is  necessary,  in  order  that  they  shall  be  retained  in  a 
stable  manner  ;  and  that  it  is  only  by  dint  of  forgetting, 
that  we  come  to  have  certain  details  present  in  our 
minds  which  escape  us  and  which  it  has  been  necessary 
to  learn  again  and  again.  The  repetition  of  the  same 
peripheral  impressions,  the  repeated  view  of  the  same 
objects,  the  hearing  of  the  same  sounds,  become  there- 
fore indispensable  fundamental  conditions  of  the  pre- 
servation of  reminiscences ;  and  from  this  point  of  view 
the  rcnn'niscences  emanating  from  the  s^wsoxi-aX  plexuses^ 
the  memory  of  the  senses,  as  they  are  pedantically  called, 
are  the  most  energetic  stimulations  of  mental  memory.* 

On  the  other  hand,  in  order  that  the  impression  per- 

*  All  those  who  have  pratically  studied  anatomy  know  how  necessary  it  is 
Ijequently  to  review  certain  regions  of  the  human  body  to  know  them  well ; 
and  that  it  is  only  after  having  seen,  touched,  and  dissected,  that  we  succeed 
in  fixing  in  our  memories  the  different  details  we  have  studied. 


GENESIS  AND   EVOLUTION   OF   MEMORY.         I45 

sistent  in  the  peripheral  plexuses  shall  produce  a  durable 
impression  in  the  central  regions,  the  preceding  condi- 
tions of  centrifugal  impression  are  not  the  only  ones 
necessary.  It  is  necessary  that  there  shall  be  some- 
thing more  on  the  part  of  these  same  central  plexuses 
of  the  seiisoriiim — an  eftective  participation  or  intimate 
association  of  their  sensibility  with  the  peripheral  exci- 
tations which  thus  throw  it  into  agitation. 

At  the  moment,  indeed,  when  the  external  impres- 
sion sets  the  peripheral  sensorial  cells  vibrating,  these 
are  affected,  according  to  the  different  modes  of  their 
natural  sensibility.  They  are  sensitized  in  a  different 
manner,  according  as  the  excitation  is  agreeable  or 
disagreeable  to  them.  In  the  first  case  a  sensation  of 
pleasure  accompanies  the  external  impressions,  in  the 
second  case  a  sensation  of  discomfort  ;  so  that  the 
nervous  element  coming  into  play  with  its  latent 
activity,  transports  to  the  sensoriimty  not  only  the  an- 
nouncement of  the  arrival  of  the  external  excitation, 
but  at  the  same  time  the  special  notion  of  pleasure  or 
pain  related  to  each  excitation. 

Every  former  impression,  every  reminiscence  that 
slumbers  within  us,  remains  there  from  the  moment  it 
has  been  perceived,  stored  up  with  a  specific  coefficient 
which  recalls  to  us  the  joy,  the  pain — or  even  the  indif- 
ference of  these  same  peripheral  plexuses  at  the 
moment  when  it  was  incorporated  with  them  and  when 
it  began  to  live  in  their  own  life. 

We  all  know  that  the  reminiscence  of  physical 
pain,  and  corporeal  chastisement,  so  lively  in  animals 
that  are  in  training,  is  for  man  one  of  the  surest 
guides  of  his  conduct,  and  a  most  faithful   warning  to 


146  THE  BRAIN  AND  ITS  FUNCTIONS. 

avoid  faults  which  will  inevitably  provoke  their  recur- 
rence. 

We  know,  conversely,  that  reminiscences  of  agreeable 
impressions,  and  those  which  have  given  us  most  joy,  are 
also  those  which  have  the  deepest  roots  in  us,  and  that 
in  fact  different  states  of  emotivity,  associated  with  the 
arrival  in  the  sensoriiun  of  such  and  such  a  group  of 
external  impressions,  are  what  perpetuate  themselves 
with  the  greatest  tenacity.  They  thus  become,  as 
regards  the  desires  they  excite  or  the  aversions  they 
beget,  the  natural  pivots  around  which  all  human 
activities  gravitate. 

2.  We  have  just  seen  the  mode  of  genesis  and  trans- 
mission of  persistent  sensorial  impressions,  at  the  mo- 
ment when  they  are  begotten  in  the  peripheral  regions 
of  the  system — let  us  now  see  how  they  are  received 
in  the  plexuses  of  the  sejisorium,  and  what  reactions 
they  provoke  as  their  consequences. 

The  connections  between  the  peripheral  plexuses  and 
those  of  the  sensorium  are  so  intimate  that,  so  soon  as 
an  impression  has  been  produced  in  the  former,  their 
partner  central  regions  immediately  enter  into  unison 
with  them.  There  is  a  nervous  condition  of  similar 
pitch  which  harmonizes  one  part  with  another,  and 
whenever  the  primordial  impression  has  been  sufficiently 
intense,  and  sufficiently  prolonged,  whenever  there  has 
been  an  effective  participation  of  the  nervous  plexuses 
laid  under  contribution,  the  partner  plexuses  of  the 
se7isormm  sympathetically  associate  in  their  excitations 
and  enter  upon  a  concordant  period  of  erethism.  The 
incident  excitation  arrives  then  in  the  plexuses  of  the 
cortical    substance,    purified     and    animalized    by    the 


GENESIS  AND   EVOLUTION   OF   MEMORY.         I47 

peculiar  metabolic  action  of  the  nervous  plexuses  in  the 
womb  of  which  it  is  incarnated,  and  then,  transforming?- 
itself  into  a  psychic  excitation,  it  develops  the  latent 
energies  proper  to  the  cerebral  cells,  imprints  itself  upon 
them,  and  perpetuates  itself  in  them  in  the  form  of  per- 
sistent vibrations,  like  a  phosphoric  gleam  of  the  ex- 
ternal world. 

Thus  it  is,  that  this  mysterious  property  which  the 
nervous  elements  possess — that  of  persisting  in  the 
vibratory  condition  in  which  they  have  been  placed — 
is  here  again  found  consistent  with  itself  throughout  the 
different  stages  traversed  by  the  sensorial  excitations  ; 
from  the  peripheral  regions  where  it  reveals  itself  in  so 
indubitable  a  manner  (as  in  the  persistence  of  impres- 
sions on  the  retina),  to  the  central  regions,  where  it 
acquires  characters  entirely  dependent  upon  the  multi- 
tude of  elements  which  serve  to  maintain  it. 

Thus  it  is  then,  that  external  impressions  of  all  kinds, 
the  diverse  emotions  we  have  felt,  become  finally  attenu- 
ated in  the  plexuses  of  the  sensorium,  and  in  the  form 
of  persistent  vibratory  thrills  become  the  posthumous 
expressions  of  impressions  and  past  emotions  which 
remain  alive  in  us  when  the  primordial  excitations  have 
long  ago  disappeared. 

Sensorial  excitations,  when  they  are  diffused  in  the 
plexuses  of  the  sensormm  and  fix  themselves  there 
in  a  persistent  manner,  do  not  usually  remain  there 
in  the  state  of  vague,  uncertain  impressions.  They 
go  further,  penetrate  more  deeply  into  the  recesses  of 
cerebral  life,  and  when  they  are  sufficiently  lively  and 
often  enough  repeated,  they  penetrate  even  into  those 
inmost  regions  where  the  notion  of  conscious  personality 


148  THE   BRAIN   AND   ITS   FUNCTIONS. 

is  elaborated,  and  thus  become  conscious  reminiscences 
of  ancient  emotions  that  have  thrilled  us. 

Thus  it  is  that,  as  regards  the  phenomena  of  memory, 
our  inner  personality  is  seized  upon  by  the  same  process 
by  which  it  was  seized  upon  on  the  arrival  of  sensorial 
impressions  ;  only  that  these  impressions  which  call  it 
into  activity  prolong  their  action,  implant  themselves 
in  the  organism,  and  become,  as  it  were,  a  vibratory 
echo  of  the  past.  It  is  thus  then,  that  the  reminiscence 
of  anterior  excitations  perpetuates  itself  in  the  sensorium 
with  the  particular  coefficients  of  joy  or  sorrow  that 
have  presided  over  their  genesis  in  the  peripheral 
regions,  and  thus  a  series  of  emotions  related  to  each 
of  them  becomes  developed,  and  perpetuates  itself  in 
the  central  sensitive  regions  of  our  organism. 

The  phenomena  of  psychical  and  moral  activity, 
understood  as  we  have  previously  explained,  perpetuate 
themselves  in  a  similar  manner,  and  develop  incessantly, 
by  the  mere  calling  into  activity  of  the  two  fundamental 
processes  of  the  nerve-cells — sensibility,  and  that  pecu- 
liar retentive  power,  organic  phosphorescence,  by  means 
of  which  they  prolong  the  vibratory  excitations  which 
have  first  set  them  in  motion. 

In  the  domain  of  intellectual  activity  it  is  still  the 
same  force  that  underlies  most  of  the  dynamic  opera- 
tions to  which  this  activity  gives  birth. 

It  is,  indeed,  because  he  remembers,  because  his  sensi- 
bility has  been  impressed  in  a  special  manner,  and 
this  impression  is  persistent  in  him,  that  the  young 
child,  from  the  first  instant  of  his  life,  expresses  his 
inner  sentiments.  It  is  because  he  remembers,  that  he 
recognizes    external  objects  and   names  them  with  an 


GENESIS  AND   EVOLUTION   OF   MEMORY.        1 49 

appropriate  word,  which  he  has  retained  in  his  memory 
from  having  heard  it.  It  is  by  means  of  the  persist- 
ence of  acoustic  impressions,  preserved  in  the  state  of 
sonorous  reminiscences,  that  he  speaks,  and  that  his 
phonetic  expressions  are  applied  to  each  surrounding 
object. 

It  is  also  by  the  same  means  that  he  learns  to  trace 
written  characters,  which  he  recognizes  as  the  symbolic 
expression  of  absent  objects,  and  that  he  reads  aloud, 
transforming  each  written  character  into  sonorous 
concordant  expressions  which  he  knows  to  be  their 
equivalents. 

There  are  always  at  the  bottom  of  these  different 
operations  of  the  intelligence,  persistent  sensorial  im- 
pressions which  direct  the  processes  in  evolution,  and 
vibrate  like  a  faithful  echo  of  the  first  impression.  It 
is  the  same  with  that  admirable  faculty  which  fhe  human 
being  possesses,  the  power  of  translating  into  verbal  ex- 
pression his  emotions  and  the  thoughts  which  pass 
throughhis  mind.  It  is  because  man  has  learned  that  each 
word  expresses  an  external  object,  a  thought,  a  sentiment, 
and  because  this  acquired  notion,  preserved  by  daily  use, 
is  maintained  in  liim  in  a  state  of  permanent  freshness, 
that  he  speaks,  addresses  his  kind,  and  is  understood 
by  them.  It  is  memory — the  accumulated  reminis- 
cences always  present  to  the  mind — that  forms  the 
basis  of  his  language,  and  thus  becomes  the  inex- 
haustible store  in  which  he  finds  the  means  of  express- 
ing what  he  feels  and  what  he  thinks. 


CHAPTER  II!. 

THE   MEMORY   IN   EXERCISE. 

Besides  those  phenomena  of  memory  into  which  the 
liuman  personality  more  or  less  enters,  there  exist  a 
whole  series  of  similar  acts  which  represent  processes 
of  memory  to  some  extent  incompletely  developed. 

These  are  those  phenomena  in  which  sensorial 
excitations,  not  having  carried  their  action  as  far 
as  the  plexuses  of  conscious  personality,  remain  in 
the  condition  of  sterile  materials,  not  perceived  by  the 
seiisorium.  Like  those  dark  ultra-violet  rays  of  the 
spectrum,  which  though  not  perceptible  to  our  eyes, 
have  nevertheless  a  real  existence,  they  remain  silently 
accumulated  in  the  plexuses  of  the  cerebral  cortex,  and 
only  await  the  presence  of  an  exciting  cause  capable 
of  causing  them  to  start  from  their  obscurity. 

Thus,  we  all  know  that  during  the  period  of  our 
diurnal  activity,  there  are  a  host  of  various  impres- 
sions which  assail  us  on  all  sides,  and  even  strike 
redoubled  blows  upon  our  sensitive  plexuses,  yet  to 
which  we  pay  no  attention.  The  multifarious  noises  of 
carriages  rolling  around  us  all  day,  finally  come  to  be 
un perceived  by  us  and  indifferent  to  us.  We  know  also 
that  when  we  give  ourselves  up  to  an  absorbing  intel- 
lectual work,  the  ticking  of  the  clock  beside  us  strikes 


THE   MEMORY   IN   EXERCISE.  I51 

in  vain  upon  our  ears,  and  yet  our  acoustic  nerves  have 
been  again  and  again  set  vibrating  without  our  having 
a  notion  of  it. 

Onimus  has  made  a  very  curious  observation  in  con- 
nection with  this  class  of  ideas.  A  man  who  was 
walking  began  automatically  humming  an  air,  being 
very  much  surprised  by  its  having  come  into  his  head. 
It  was  only  accidentally  that  he  perceived  that  the  air 
had  been  suggested  to  him  by  a  wandering  musician 
who  was  playing  it  on  his  instrument  as  he  passed  by, 
and  whom  he  had  not  perceived.*  This  man  in  humming 
the  air  echoed  an  auditory  impression,  an  unconscious 
reminiscence. 

We  all  know  that  in  examining  a  picture,  or  land- 
scape, or  a  histological  preparation,  we  first  passively 
see  the  whole,  and  that  certain  details  when  we  are 
not  prepared  for  them  at  first  escape  us  ;  and  if  a  per- 
son, after  we  have  gone  to  a  distance  from  the  object 
we  have  examined,  retrospectively  calls  to  our  notice 
certain  peculiarities  of  the  object,  we  are  quite  astonished 
that  we  have  remarked  them,  and  that  we  recognize  in 
ourselves  the  existence  of  certain  impressions  which 
have  remained  silent. 

It  is  by  means  of  unconscious  impressions  which 
persist  in  the  brain  that  the  activity  of  our  spirit,  in 
the  automatic  work  which  takes  place  in  the  act  of 
reflection  and  meditation,  is  maintained. 

It  is  thus  that  the  unexplored  sides  of  certain  ques- 
tions in  suspense  are  made  clear  by  the  juxta-position 
of  old  impressions  which  have  arisen.  A  sort  of  auto- 
matic appeal  is  made  to  revived  impressions  which  have 

*  Onimus,  "Journal  d'Anat.  et  Thysiol.,"  de  Robin,  p.  551,  1873. 


152  THE  BRAIN   AND   ITS   FUNCTIONS. 

some  connection,  and  which  come,  as  new  factors,  to 
enlighten  our  judgments  with  a  number  of  new  ideas. 

The  symptomatic  study  of  mental  maladies  presents, 
as  regards  the  subject,  phenomena  which  are  often  very 
curious.  We  sometimes  meet  persons  who  have  received 
an  excellent  education — ladies,  young  girls,  living  in  the 
best  society,  above  all  taint  of  impurity,  w^ho,  when 
seized  with  an  attack  of  cerebral  excitement,  utter  the 
grossest  words,  quite  strange  to  their  ordinary  voca- 
bulary. 

Evidently,  in  these  cases,  the  phenomena  can  only  be 
explained  thus  : — That  in  walking  in  the  streets  or  in 
public  places,  these  gross  phrases  have  unconsciously 
impressed  them,  and  have  remained  in  the  state  of 
latent  memories  buried  in  the  cerebral  tissue  ;  an<f  that 
it  is  because  of  the  morbid  over-activity  of  the  regions 
in  which  they  are  stored  up  that  they  are  discovered 
and  leap  to  light. 

Local  Memories. — It  results  from  the  anatomical 
arrangements,  to  which  we  have  so  many  times  directed 
attention,  that  the  different  groups  of  sensorial  impres- 
sions have  each  a  special  territory  of  distribution  in  the 
different  regions  of  the  sensorium,  and  that  consequently 
there  are  in  the  human  brain  inequalities  very  clearly 
distinguished  as  regards  the  part  devoted  to  each  par- 
ticular order  of  sensorial  impressions.     (Figs.  5  and  6.) 

It  follows  then  from  this  inequality  of  development 
of  similar  regions  in  different  individuals,  that  there 
exist  special  aptitudes  for  the  reception  of  the  different 
kinds  of  sensorial  impressions.  Thus  it  is  that  one 
person,  whose  optic  cerebral  regions  are  abundantly  pro- 
vided with  well-endowed  lively  nerve-cells,  will  be  fitted 


THE   MEMORY  IN   EXERCISE.  153 

for  clear  perception  of  the  external  world — surrounding 
objects,  with  their  colours  and  relations ;  that  another 
(Fig.  6. — 14,  15),  whose  acoustic  cerebral  regions  are 
largely  developed  will  be  predisposed  to  appreciate 
all  the  shades  and  delicacies  of  musical  harmony ; 
while  a  third  will  have  such  and  such  an  aptitude 
according  to  the  preponderance  of  such  and  such  a 
region  of  his  brain  ;  and  that  thus,  the  special  sensorial 
impressions,  finding  within  such  or  such  a  circumscribed 
locality  conditions  of  soil  more  favourable,  agglomera- 
tions of  cells  more  dense  and  more  lively — these  impres- 
sions will  leave  more  enduring  records,  more  vivid 
remembrances,  and  from  this  very  fact  richer  stores  of 
materials  for  fertilizing  the  psycho-intellectual  activity 
in  such  or  such  a  direction. 

We  are  thus  led  to  the  conclusion  that  there  are  in 
the  phenomena  of  memory,  taken  as  a  whole,  certain 
peculiarities,  by  virtue  of  which  this  memory  is  more  or 
less  vivid  in  such  or  such  an  individual  as  regards  such 
or  such  a  cerebral  operation,  and  that  thus  there  are  a 
certain  number  of  local  memories  very  clearly  deter- 
mined, each  having,  in  a  manner,  an  autonomy  as  inde- 
pendent as  the  generating  sensorial  impressions  with 
which  it  is  intimately  associated. 

Association  of  Meinories. — The  study  of  the  brain  has 
shown  us  that  there  are  isolated  regions  designed  to 
receive  and  elaborate  independently  isolated  groups 
of  sensorial  impressions.  The  study  of  the  cortex,  on 
the  other  hand,  has  shown  us  that  if  there  be  a  certain 
functional  autonomy,  as  regards  the  dispersion  of  im- 
pressions, this  autonomy  is  neither  complete  nor  defini- 
tive, seeing  that   examination   of  the   nervous  tissue  of 


154  THE  BRAIN  AND   ITS   FUNCTIONS. 

the  cortex,  proves  that  this  tissue  forms  a  continuous 
whole  throughout  all  its  extent,  a  unity  as  complete  as 
that  of  the  cutaneous  surface — so  that  the  excitations 
perceived  at  a  given  moment,  in  a  certain  region  of 
the  sensormm^  are  nevertheless  liable  to  be  disseminated 
at  a  distance,  and  to  associate  the  different  regions  of 
the  cerebral  tissue  in  their  vibration.     (Figs.  I  and  6.) 

Thus,  for  instance,  when,  in  the  presence  of  a  picture, 
a  landscape,  or  any  object  which  may  catch  our  eye, 
the  special  regions  of  our  brain  which  elaborate  optic 
impressions  are  thrown  into  activity,  it  is  only  homo- 
geneous optic  impressions,  and  nothing  but  optic  im- 
pressions, which  are  active  in  a  determinate  region  of 
the  cortex. 

When,  on  the  other  hand,  my  view  extends  over  a 
landscape,  or  over  a  flower-bed  balmy  with  fragrant 
emanations  ;  when  I  am  present  at  a  theatrical  repre- 
sentation in  which  the  splendours  of  the  mise  en  scene 
equal  the  magnificence  of  the  musical  harmony,  my 
brain  is  no  longer  excited  by  a  homogeneous  stimulus  ; 
it  is  assailed  by  a  series  of  simultaneous  impressions 
which  come  in  a  crowd  and  impress  themselves  all  at 
once  upon  the  sensoriuni. 

These  simultaneous  impressions — optic,  olfactive, 
acoustic,  received  at  the  same  moment,  and  in  several 
circumscribed  localities  at  the  same  time,  constitute  a 
series  of  contemporaneous  souvenirs  which  are  created 
and  implanted  in  me  ;  and,  henceforth,  those  vibrations 
which  were  born  together,  and  were  simultaneously 
conceived,  will  represent,  in  the  general  series  of  my 
reminiscences,  a  definite  group,  of  which  the  elements, 
united  by  the  bonds  of  a  mysterious  federation,  will  all 


THE   MEMORY  IN   EXERCISE.  1 55 

live  with  the  same  life,  anastomose  one  with  another, 
and  recall  one  another  as  soon  as  one  link  of  the  chain 
is  struck. 

Thus  it  is  that  the  sight  of  even  a  corner  of  the 
landscape  I  hrst  saw,  or  of  the  flower-bed  that  grati- 
fied my  sense  of  smell,  will  recall  to  me  the  odour  of 
the  plants  that  I  had  pleasure  in  smelling,  and  even  the 
emotions  that  I  experienced  at  that  very  moment ;  and 
inversely,  these  perfumes  accidentally  inhaled  at  a  later 
period,  will  evoke  in  me  automatically  a  reminiscence  of 
/  the  place,  the  flower-bed,  where  they  were  simulta- 
neously inhaled.  Thus  it  is,  again,  that  the  sight  of 
such  or  such  a  theatrical  decoration  will  remind  me  of 
the  piece  of  music  heard  in  its  presence,  and  that,  in 
the  same  way,  if  under  other  circumstances  I  hear  the 
strains  that  have  impressed  me,  I  shall  feel  awakened 
within  me  reminiscences  connected  with  it,  which  will 
represent  to  me  the  decorations  and  the  ocular  spec- 
tacle in  the  presence  of  which  I  heard  the  musical 
sounds  for  the  first  time. 

By  taking  more  and  more  complex  examples,  we 
find  that  in  the  ordinary  phenomena  of  cerebral  activity, 
not  merely  are  binary,  ternary,  or  quaternary  groups  of 
sensorial  impressions  juxtaposed  and  imprinted  upon 
the  senscriinn,  but  many  multiple  agglomerations  are 
created  within  us  and  proceed  from  all  the  sensibilities 
of  the  organism  successively  and  simultaneously  laid 
under  contribution. 

Thus  the  pleasures  of  gastronomy  may  easily  be  allied, 
as  Brillat-Savarin  has  so  well  explained,  with  all  other 
pleasures ;  the  seductions  of  physical  pleasure,  which 
are  the  synthesis  of  all  the  sensibilities  of  the  organism 


156  THE  BRAIN  AND   ITS  FUNCTIONS. 

in  agitation,  leave  in  the  sensoriinn  traces  all  the  deeper, 
and  memories  all  the  more  vivid,  because  they  represent 
a  series  of  juxtaposed,  successive,  partial  impressions, 
which  multiply  each  other,  and  mutually  co-operate, 
so  that  they  appeal  to  one  another,  associate  in  a 
thousand  forms,  and,  thus  implanted  by  their  innu- 
merable roots  in  the  sensorium,  become  like  a  series 
of  conjugated  foci  for  exciting  in  it  a  condition  of 
erethism. 

This  curious  property  which  sensorial  impressions 
received  at  the  same  time  possess,  and  which  consti- 
tutes as  it  were  natural  families  among  them,  is  a  great 
resource  in  the  education  of  the  intellect,  and  the 
methodic  cultivation  of  its  faculties.  When  a  series  of 
memories,  a  series  of  ideas,  of  experimental  facts  and 
scientific  principles,  has  been  imprinted  on  it,  it  admits 
of  their  being  artificially  evoked,  contenting  itself  with 
an  appeal  to  the  first  in  the  series  of  memories,  which 
is  in  a  manner  at  the  head  of  the  line. 

Thanks  to  this  connection  between  our  particular 
reminiscences,  the  intelligence  incessantly  acquires  new 
riches,  and  may  at  a  given  moment,  by  means  of  its 
automatic  activity,  seize  upon  these  riches  and  make  use 
of  them. 

Thus,  when  from  observation  of  a  clinical  fact,  for 
instance,  we  have  learned  that,  a  case  of  acute  rheu- 
matic arthritis  being  given,  this  condition  of  efiusion 
into  the  joints  is  accompanied  by  a  similar  manifes- 
tation as  regards  the  heart,  these  two  impressions  hence- 
forward form  in  the  mind  two  united  memories  ;  so  that, 
the  first  being  given,  the  second  immediately  arises,  and 
vice  versa.     In  the  presence  of  a  patient  with  rheuma- 


THE   MEMORY   IN    EXERCISE.  1 57 

tism  we  think  of  a  cardiac  affection,  and  conversely  in 
the  presence  of  an  old  affection  of  the  heart,  we 
interrogate  the  patient  as  to  his  rheumatismal  ante- 
cedents. 

When  I  have  learnt  from  the  experience  of  my  masters 
that  lesions  of  the  posterior  roots  and  posterior  columns 
of  the  cord  are  accompanied  by  defective  co-ordination  of 
movements,  ocular  disturbances,  sharp  sudden  pains  in 
the  limbs,  gastric  troubles,  etc.,  I  have  anastomosed  in  my 
mind  by  study  a  series  of  memories  associated  one  with 
another  and  forming  a  sort  of  federation  ;  so  that  when 
one  happens  to  be  isolatedly  evoked — when,  for  instance, 
1  see  a  patient  with  special  ocular  troubles,  I  spontane- 
ously think  of  defective  co-ordination  of  his  movements, 
the  existence  of  sharp  sudden  pains,  etc. 

What  here  takes  place  in  an  order  of  facts  clearly 
determined,  with  regard  to  a  series  of  phenomena 
methodically  regulated,  is  constantly  and  regularly 
renewed  in  us  during  the  period  of  our  daily  acti- 
vity. 

When  every  region  of  our  brain  is  in  erethism, 
we  all  know  how  memories  appeal  one  to  another ; 
always  following  the  same  series  in  their  method  of 
appearing,  without  our  being  able  to  command  them. 
It  is  sufficient  to  see  an  object  or  a  person — to  hear  a 
name  pronounced  accidentally,  to  smell  an  odour — in 
order  to  feel  arising  within  us  a  series  of  ideas  which 
arose  at  the  moment  when  this  impression  was  at  first 
perceived  by  us.  W^e  all  know  how  frequently  in  current 
conversation  a  word — a  simple  sound — causes  the  primi- 
tive direction  of  our  ideas  to  diverge.  Many  persons 
indeed  thus  lose  sight  of  the  point  of  departure,  acci- 


158  THE  BRAIN   AND   ITS   FUNCTIONS. 

dentally  led  away  by  a  passing  reminiscence  which 
introduces  divergent  thoughts,  and  insensibly  causes 
them  to  turn  aside  from  the  subject  with  which  they 
have  started. 

Do  we  not  all  know  that  when  we  wish  at  a  given 
moment  to  evoke  a  particular  reminiscence,  and  fear 
that  the  distractions  of  our  current  life  will  cause  us  to 
forget  it,  we  mentally  attach  the  object  to  some  sign, 
which  thus  becomes  for  us  the  clue  that  recalls  it  to  our 
mind.  Every  one  has  his  own  mnemonic  on  such 
occasions,  and  we  all  know  that  it  is  sometimes  a  knot 
made  on  a  pocket-handkerchief — an  object  which 
must  necessarily  pass  through  our  hands,  a  ribbon  fixed 
upon  our  garments,  a  visible  mark  designed  to  catch 
our  eye  mechanically,  to  which  we  have  recourse,  in 
order  to  cause  the  reminiscence  we  wish  to  evoke  to 
leap  forth  in  the  natural  course  of  events.* 

*  In  the  practice  of  mnemonic  methods  we  know  that  our  end  is  the  associa- 
tion of  a  series  of  reminiscences  difficult  of  retention,  by  the  help  of  strange 
combinations  of  words ;  these  words,  easy  to  retain  by  reason  of  their  strange- 
ness, containing  in  themselves  analytic  solutions  of  the  difficult  points  we 
seek  to  fix  in  the  maniory. 


CHAPTER    IV. 

DLVELOPMENT   OF   TIJE   PHENOMENA  OF   MEMORY. 

The  general  faculty  of  memory,  the  organic  phos- 
phorescence of  the  nervous  elements,  is  liable  to  present 
great  modifications,  according  as  it  is  considered  at  the 
different  periods  of  the  development  of  the  human 
being.  It  goes  through  successive  phases,  which  are 
merely  more  or  less  direct  reflexes  of  the  histolocj-ical 
properties  of  the  cells,  by  means  of  which  it  reveals 
itself. 

In  young  children  the  cerebral  cells  are  endowed  with 
special  histological  characters ;  they  are  flabby,  greyish, 
flexible  in  a  manner ;  they  are,  moreover,  from  the 
dynamic  point  of  view,  virgin  to  any  anterior  impres- 
sion. The  sensorial  excitation  that  affects  them  at  that 
age  must  therefore  imprint  itself  upon  them  more 
readily,  since  it  finds  them  in  a  state  of  vacuity, 
their  power  of  retention  not  being  as  yet  put  to  the 
test. 

On  the  other  hand,  in  the  first  years  of  life  the  cere- 
bral substance  is  in  perpetual  exercise  and  organic 
development.  New  elements  are  perpetually  being 
added  to  the  old  ones,  and  as  the  new  are  most  pro- 
bably derived  from  their  predecessors,  we  are  led  to 
conclude  that  the  daughter-cells  which  appear,  borrow 


l60  THE   BRAIN   AND   ITS   FUNCTIONS. 

from  the  mother-cells  which  give  them  birth  an  inevit- 
able bond  of  relationship,  a  species  of  hereditary  trans- 
mission of  the  different  states  of  the  mother-cells  from 
whence  they  spring.  It  is,  then,  probable  that  the 
primordial  cells,  which  give  birth  to  all  the  generations 
of  daughter-cells  that  appear  in  the  course  of  cerebral 
development,  transmit  to  their  descendants  the  special 
sensitive  properties,  the  specific  degrees  of  phosphores- 
cence, with  which  they  were  animated  at  the  moment  of 
their  origin  ;  and  that  it  is  in  these  intimate  connections 
between  cell  and  cell,  in  these  mysterious  bonds  of 
relationship,  that  we  must  look  for  the  secret  of  the 
perennial  character  of  certain  memories.  Thus  it  is  that 
certain  impressions  received  in  our  early  childhood 
become  the  common  patrimony  of  certain  families  of 
cells,  which  maintain  them  in  a  state  of  freshness,  in- 
cessantly vivifying  them  by  a  sort  of  permanent  co-opera- 
tion. 

In  the  young  child  the  impressionability  of  the 
cerebral  substance  is  such  that  it  retains,  motii  proprioy 
all  the  impressions  that  assail  it,  as  passively  as  a 
sentized  photographic  plate  that  we  expose  to  the  light 
retains  all  the  images  that  are  reflected  on  its  surface. 

Visual  and  sensitive  impressions  are  the  first  to  be 
inscribed  upon  the  sensorium. 

The  child  sees  objects  and  persons  that  interest 
him,  within  a  restricted  circle.  These  first  impressions 
captivate  him,  and  he  keeps  the  remembrance  of  them, 
individually  recognizing  each  person  or  thing.  Little 
by  little,  auditory  impressions  coming  into  play,  he  hears 
sounds,  which  are  vague  at  first,  without  comprehending 
or  interpreting  them  ;  and  insensibly,  by  the   eft'ect  oi 


DEVELOPMENT  OF  THE  PHENOMENA  OF  MEMORY.    l6l 

the  activity  of  the  brain,  from  the  persistence  of 
the  impressions  and  the  notion  of  them  that  he 
acquires,  he  comes  to  recognize  that  these  determinate 
sounds  answer  to  precise  objects,  which  are  always  the 
same,  and  which  in  some  way  interest  his  personahty. 

Little  by  little,  this  work  of  cerebral  culture  bein^c^ 
pursued  without  cessation,  new  acquisitions  are  inces- 
santly registered  in  the  sensoriiiui.  The  different  modes 
of  sensibility  awakened  bring  with  them  new  ideas  and 
new  remembrances,  and  at  the  same  time  excite  appro- 
priate reactions.  The  regions  of  intellectual  activity 
begin  to  make  more  and  more  use  of  the  excitations 
which  come  from  the  surrounding  world  to  crethise 
them. 

At  this  happy  age  t^ie  child  retains  what  he  sees, 
hears,  tastes,  without  trouble.  The  strangest  words, 
complete  phrases  that  he  does  not  comprehend,  abstract 
proper  substantives,  pieces  of  poetry,  the  operations  of 
mental  calculation,  leave  in  him  persistent  impressions 
which  are  perpetuated  and  registered  in  a  stable  manner. 
It  is  this  special  period  of  complete  absorption,  w^hich  we 
might  call  the  age  of  substantives^  that  represents  in 
the  history  of  the  development  of  the  human  being 
the  first  rudiments  of  intellectual  activity,  as,  in  the 
history  of  the  development  of  humanity  in  general,  the 
stone  age  represents  the  first  outlines  of  human  labour.* 

*  Substantives  play  a  principal  part  in  the  evo'ution  of  thought  and  speech. 
They  are  the  primordial  data  around  which  the  verb  and  the  other  parts  of 
speech  group  themselves.  They  are  the  elements  that  underlie  the  combina- 
tions of  human  thought.  The  facility  with  which  they  disappear  from  the 
memory  in  certain  cases  of  cerebral  disorganization  suggests  the  thought  that 
from  the  first  periods  of  intellectual  development,  they  are  really  received  and 
■stored  up  in  isolated  territories  of  nerve-cells  which  serve  them  as  a  sut> 
Sliai'un,  in  the  form  of  persistent  sensorial  impressions. 


l62  rilE   BRAIN   AND   ITS   FUNCTIONS. 

In  the  adult  the  elements  of  cerebral  activity  in  a 
condition  of  complete  development  are  endowed  with 
all  the  energies  they  are  capable  of  assuming.  They  do 
not  now  behave  as  they  did  in  the  young  child  during 
the  period  of  his  evolution,  as  far  as  regards  the  preser- 
vation and  storing  up  of  external  excitations. 

The  period  of  saturation  begins  for  the  cerebral  cell. 
The  power  of  retention  of  external  excitations  is  already 
on  the  brink  of  decay.  New  acquisitions  of  heteroge- 
neous elements  which  do  not  form  a  portion  of  the 
circle  of  youthful  knowledge  become  very  difficult,  if 
not  impossible.  We  know  how  painful  the  labour 
of  learning  a  foreign  language,  so  easy  for  the 
young  child,  becomes  for  the  adult  ;  how  rebellious  the 
memory  is  as  regards  the  registering  of  new  words  ; 
and  with  what  an  expenditure  of  intellectual  force  we 
retain  the  vocabulary  of  languages  with  which  we  were 
not  familiar  in  childhood.  We  also  know  how  blunt, 
even  in  the  domain  of  common  things,  the  retentive 
power  of  our  memory,  and  consequently  our  powers  of 
appHcation  in  general,  become,  if  we  have  to  learn 
things  that  are  quite  new  to  us ;  and  how,  for  instance, 
we  with  reason  look  upon  it  as  impracticable  to  acquire 
a  special  technical  education,  and  con^mence  a  new 
career  after  forty  years  of  age. 

At  this  period  of  life  first  impressions  still  faithfully 
persist  in  the  memory,  but  nevertheless  they  have  a 
tendency  to  diminish  in  intensity,  and  it  us  necessary  to 
vivify  them  by  incessant  labour,  to  stimulate  them  anew 
by  placing  the  cerebral  regions  where  they  are  stored  up 
in  identical  conditions,  by  similar  impressions  of  equal 
intensity,  so  as  to  prevent  their  becoming  extinct ;  just 


DEVELOPMENT  OF  THE  PHENOMENA  OF  MEMORY.    163 

as  we  keep  up  a  fire  by  continually  supplying  it  with 
fresh  material. 

As  the  entire  human  frame  begins  to  suffer  from  the 
effects  of  senescence,  which  occurs  in  different  individuals 
at  very  different  periods,  the  cerebral  cells,  like  the  other 
elements  of  the  organism,  suffer  a  premature  decay. 

They  grow  old  histologically  ;  they  become  more  or 
less  infiltrated  with  fatty  granular  matter  ;  they  cease  to 
be  transparent,  shrivel  up,  and  from  a  dynamic  point  of 
view  insensibly  loce  a  portion  of  their  sensibility  and 
their  special  retentive  power  ;  so  that,  as  foci  of  organic 
phosphorescence,  it  may  be  said  that  they  are  extin- 
guished within  certain  circumscribed  localities  of  the  cere- 
bral cortex,  and  consequently  cease  to  preserve  a  record 
of  their  first  impressions.  Thus  it  is  that  the  general 
phenomena  of  mental  activity  undergo  a  perceptible 
decay  proportional  to  the  sum  of  the  cerebral  elements 
superannuated.  In  the  a;;ed,  memories  sometimes  dis- 
appear in  an  isolated  manner ;  sometimes  those  which 
are  not  maintained  by  regular  exercise  become  extinct; 
sometimes  the  general  faculty  of  memory  fails  altogether, 
and  in  its  decay  involves  the  progressive  blunting  of 
the  most  lively  sentiments. 

A  strange  phenomenon  now  occurs — we  perceive, 
contrary  to  what  a  priori  would  seem  most  probable, 
that  in  old  persons,  as  in  patients  with  dementia, 
old  memories  remain  the  freshest  and  most  vivid, 
while  recent  facts,  impressions  which  occur  at  the  very 
moment,  are  unperceived  and  treated  as  if  they  did  not 
exist.  It  is  probable  that  at  this  period  of  life,  the  cells 
of  the  sensoriuin,  altered  in  their  essential  constitution, 
have  become  lazy,  and  incapable  of  erecting  themselves 


1 64  THE   BRAIN   AND   ITS   FUNCTIONS. 

in  the  presence  of  recent  external  impressions  ;  and  that 
this  state  of  torpidity  of  the  elements  of  the  sensorium 
for  new  excitations,  leaves  the  field  free  to  the  older 
ones  which,  not  being  obscured  by  more  lively  impres- 
sions, continue  to  vibrate  without  opposition,  and  thus 
perpetuate  the  last  phosphorescent  gleams  of  a  far-off 
past  which  is  dying.* 

*  Thus,  in  some  old  persons  in  dementia,  from  the  mere  fact  of  the  non- 
absorption  of  recent  impressions  into  the  sensorium,  the  notion  of  the  passage 
of  time  is  completely  annihilated. 

From  the  fact  that  the  daily  work  of  the  absorption  of  new  impressions 
has  ceased,  the  individual  remains  fixed  in  one  spot,  as  it  were,  in  a  cataleptic 
state,  with  the  ideas  and  preoccupations  that  he  had  at  a  given  moment  of  his 
existence.  Thus,  we  see  a  great  number  of  patients  who,  having  been  some 
ten  or  twelve  years  in  an  asylum,  still  keep  the  ideas  they  had  at  the  moment 
of  their  entrance,  without  having  an  idea  of  the  passage  of  time;  and  who,  ii 
asked  how  long  they  have  been  there,  will  spe.ik  of  two  or  three  years. 


CHAPTER   V. 

FUNCTIONAL  DISTURBANCES  OF   THE   PHENOMENA 

OF  MEMORY. 

The  manifestations  of  memory,  looked  at  as  we  have 
just  done,  do  not  then  present  themselves  merely  as  a 
collection  of  simple  phenomena,  nor  as  the  direct 
resultant  of  the  impression  made  upon  the  plexuses 
of  the  cortical  substance  by  an  external  excitation. 
They  consist  in  true  physiological  processes,  which  have 
an  origin  and  a  regular  evolution  throughout  the  nervous 
system.  They  demand  the  active  participation  of  the 
cerebral  cell ;  and  to  be  regularly  executed  they  must 
obey  certain  organic  necessities,  and  the  inevitable  con- 
ditions of  integrity  and  co-operation  of  the  organs 
through  which  they  effect  their  complete  development. 

When,  therefofe,  any  disturbance  whatever  occurs 
either  in  the  essential  vitality  or  in  the  constitution  of  the 
organic  elements  which  they  lay  under  contribution,  the 
processes  of  memory  are  ipso  facto  disjointed,  and  that 
faculty  is  thus  maimed  in  one  or  other  of  the  operations 
that  constitute  it. 

Tlius  there  are  circumstances  in  which  that  property 
which  the  nervous  elements  possess,  of  retaining  a  record 
of  external  excitations  which  have  formerly  impressed 
them,  attains  a  condition  of  extreme    and  permanent 


1 66  THE  BRAIN   AND   ITS   FUNCTIONS. 

exaltation.  This  vibratory  phase  of  their  existence 
perpetuates  itself  and  becomes  a  species  of  unsubduable 
erethism. 

All  phyiologists,  indeed,  have  recognized  the  impor- 
tant part  a  sudden  emotion,  such  as  terror  or  the  sight 
of  an  epileptic  attack,*  plays  in  the  production  of  convul- 
sive seizures  ;  and  I  have  further  pointed  out  that  violent 
impressions  may  remain  stereotyped  in  certain  indi- 
viduals attacked  with  general  paralysis,  and  that  the 
shock  caused  in  the  sensorium  may  be  very  vivid,  since 
it  is  capable  of  manifesting  itself  for  several  consecutive 
months  in  a  species  of  cataleptic  condition,  imprinted 
upon  the  countenance,  and  upon  the  attitudes  of  the 
body.f 

The  symptoms  presented  by  the  automaton  whose  in- 
teresting case  has  been  reported  by  Mesnet,  come  under 
this  class  of  facts.  There  are  in  such  cases  persistent 
impressions,  which  have  been  formerly  accumulated  in 
the  automatic  sensorium,  which  continues  to  direct  the 
excito-motor  processes  without  participation  of  the  con- 
scious personality. 

Van  Swieten,  who  was  seized  with  vomiting  on  coming 
upon  the  dead  body  of  a  dog  which  exhaled  an  insup- 
portable stench,  chanced  upon  the  same  spot  some 
years  afterwards.  The  memory  of  what  he  had  ex- 
perienced produced  the  same  disgust  and  the  same 
consequences  % 

This  class  of  morbid  phenomena  is  always  developed 
by  virtue  of  the  same  physiological  processes  as  those 

*  See   Luys,    "Actions  reflexes  cerebrales,"   p.    83.     Morbid  phenomena 
resulting  from  a  persistenl  impression.     (Paris,  1854.) 
t  Luys,  loc.  cit.,  pp.  73  and  87. 
5  "Annales. Medico  pb}cliol."  1851,  p.  242.    Fact  cited  by  Parchappe, 


FUNCTIONAL   DISTURBANCES   OF   THE   MEMORV.    16/ 

ivliich  regulate  the  manifestations  of  normal  activity. 
There  are  latent  and  si'ent  stimulations  which,  by  reason 
of  certain  conditions  which  have  presided  over  their 
impression  upon  the  organism,  remain  more  vivid  than 
others,  and  which,  by  virtually  becoming  incessantly- 
active  stirntili,  produce  a  discharge  of  nervous  force, 
either  in  the  form  of  interrupted  convulsive  currents, 
in  that  of  continuous  motor  currents  (cataleptic  con- 
dition of  the  muscles),  or  in  that  of  sympathetic  reactions 
from  the  side  of  vegetative  life  (vomiting,  etc.). 

In  other  circumstances,  we  have  no  longer  to  deal 
with  an  isolated  phenomenon,  revealing  itself  by  definite 
manifestations,  and  reflecting  as  before  the  deviations 
of  a  normal  process  regularly  accomplished.  We  ob- 
serve, in  fact,  manifestations  of  quite  a  different  kind, 
which  reveal  themselves  by  a  species  of  exaltation  of 
the  psycho-intellectual  regions,  which  preserve  and  store 
up  external  impressions  in  a  very  vivid  manner,  and  when 
the  cerebral  elements  have  risen  above  their  usual  pitch, 
manifest  their  new  condition  by  an  unexpected  super- 
activity quite  contrary  to  the  habits  of  cerebral  life  of 
the  individual. 

We  see  patients,  indeed,  gifted  with  very  ordinary  hi  • 
telligence,  who,  when  in  this  phase  of  cerebral  erethism, 
will  improvise,  make  quotations,  associate  new  ideas 
with  extreme  rapidity,  say  witty  things  and  make  puns — 
things  they  are  quite  incapable  of  doing  when  in  their 
ordinary  vital  condition. 

Michea  cites  the  case  of  a  young  butcher  whom  he  ob- 
served in  the  Bicetre,  and  who,  under  the  influence  of  an 
attack  of  mania,  recited  whole  speeches  from  the  PJiedrc 
of  Racine.     During  an  interval  of  calm,  he  said  he  had 


1 63  THE   BRAIN   AND  ITS   FUNCTIONS. 

but  once  heard  the  tragedy  in  question,  and  that,  spite 
of  all  his  efforts,  he  could  not  recite  a  single  verse. 

Van  Swieten  cites  from  the  same  author  the  case  of 
a  young  workman,  who,  never  having  dreamed  of 
making  v^erses,  during  an  attack  of  fever  became  a  poet 
and  inspired.  Perfect  speaks  of  a  lunatic,  who,  during  his 
delirium,  expressed  himself  in  very  harmonious  English 
verse,  although  previously  he  had  never  shown  any  dis- 
position for  poetry.  Tasso  is  said  to  have  worked  better 
during  an  attack  of  mania,  than  in  his  lucid  intervals.* 

Finally,  in  other  circumstances  we  observe  phenomena 
of  an  entirely  inverse  character.  Far  from  being  pheno- 
mena of  over-excitement  of  the  memory,  they  are  those 
of  dislocation  and  clouding  over. 

Persons  thus  affected,  more  or  less  completely  lo§e  the 
faculty  of  retaining  certain  memories  ;  either  through 
the  destruction  of  certain  circumscribed  regions  in  the 
cortical  substance,-]-  or  through  the  progressive  destruc- 
tion of  its  elements. 

Similarly  there  are  certain  persons  with  dementia  who, 
being  affected  with  partial  amnesia,  forget  the  date  of 
the  day  and  year  in  which  they  live  ;  they  do  not  know 
their  way,  lose  themselves  in  the  streets,  and  yet  they 
are  still  able  to  sustain  a  certain  amount  of  current  con- 
versation. Others,  on  rising  from  table  forget  they  have 
had  their  dinner,  and  order  it  to  be  served  up.  Others, 
after  receiving  a  visit  from  their  relations  or  friends,  and 

*  Michia,  "  Aiinales  Me(iico-p?;ycliol.,"  i860,  p.  302. 

f  Voisin  has  pointed  out  a  case  of  amnesia  with  softening  of  the  cerebral 
luijatance.  The  patient  had  io  t  the  memory  of  objects,  and  had  for^jo  en 
names  and  substantives.  If  a  spoon  were  presented  to  him  he  could  not  teU 
the  name  of  it,  but  showed  by  his  gestures  that  it  was  for  eating  soup  with. 
("Societie  Anatomique,"  1867,  p.  342.) 


FUNCTIONAL  DISTURBANCES  OF  THE   MEMORY.    169 

conversing  with  them,  when  the  visit  is  fairly  over — an 
hour  afterwards — retain  no  definite  impression  about  it, 
or  else  make  mistakes  ;  when,  for  instance,  they  have 
received  a  visit  from  their  daughter,  they  will  say  they 
have  had  one  from  their  grandfather,  etc. 

There  are  others  again  who,  although  enjoying  a  cer- 
tain portion  of  their  faculties  and  the  capacity  for 
speaking  regularly,  lose  little  by  little  the  memory  of 
proper  names,  then  that  of  substantives,  then  of  verbs, 
and  make  mistakes  in  orthography.  Cuvier,  in  his 
lectures,  mentions  the  case  of  a  man  who  had  lost  the 
memory  of  substantives,  and  who  could  form  sentences 
very  well,  with  the  exception  of  names,  which  he  left 
blank* 

It  is  curious  to  remark,  as  J.  Falret  has  done,  that  in 
this  process  of  decay  which  takes  place,  the  human 
mind  in  despoiling  itself  of  its  wealth,  loses  it  chrono- 
logically in  the  order  in  which  it  has  accumulated  it. 
Thus  it  is  the  remembrance  of  proper  names  which  is 
first  extinguished ;  these,  as  we  have  previously  remarked, 
p.  161,  representing  the  first  periods  of  the  work  of  the 
intelligence  in  ascending  evolution.  Then  come  com- 
mon names,  adjectives  and  verbs,  which  represent  a 
more  advanced  degree  of  the  perfectionment  of  the 
faculties,  when  the  child  has  begun  to  express  his  will 
by  means  of  appropriate  verbs. 

Thus  in  these  periods  of  progressive  decadence  the 
processes  of  memory  being  gradually  deprived  of  the 
materials  by  means  of  which  they  effect  their  manifes- 
tations, cease  to  be  regularly  evolved  ;  amnesia  advances 
further  and  further,  and  we  see  individuals  thus  affected 

•  "Annales  Mcdico-psychol.,"  1852,  p.  30^. 
13 


I/O  THE  BRAIN   AND  ITS  FUNCTIONS. 

quite  incapable  of  registering  present  Impressions,  pre- 
serving no  remembrance  of  what  passes  around  them, 
forgetting  the  past,  and  becoming  more  and  more 
incapable  of  expressing  their  sentiments  and  wishes,  in 
consequence  of  the  progressive  wearing  out  of  the 
organic  apparatuses  that  serve  for  the  evolution  of  the 
processes  of  memory. 


BOOK    III. 

AUTOMATIC    ACTIVITY    OF    THE    NERVOUS 

ELEMENTS. 


CHAPTER  L 

INTRODUCTORY. 

The  automatic  activity  of  the  nervous  elements,  like 
their  histological  sensibility,  is  merely  one  of  the  special 
forms  of  their  peculiar  vitality. 

Diffused,  in  a  similar  manner,  in  its  most  simple  forms, 
through  the  most  elementary  organisms,  this  automatic 
activity  is  perfected,  and  amplified,  in  proportion  as  it 
is  distributed  through  more  abundant  and  more  dense 
agglomerations  of  cells,  which  are  at  the  same  time 
endowed  with  a  more  intense  vital  energy. 

It  reveals  itself  in  its  most  simple  forms,  as  a 
histologic  property  of  the  free  cells,  the  white  corpuscles 
of  the  blood  ;  of  that  series  of  cells  with  mobile  pro- 
longations (vibratile  cilia,  spermatozoids),  whose  auto- 
matic energy  is  manifested  in  such  characteristic  amoeboid 
movements  ;  and  finally  of  isolated  masses  of  protoplasm. 

As  we  ascend  in  the  zoological  series,  we  perceive  that 
the  manifestations  of  automatic  life  consist  not  merely 
in    purely  local  phenomena,  in  which  the  histologic  ele- 


1/2  THE  BRAIN   AND   ITS   FUNCTIONS. 

ments  accomplish  the  natural  phases  of  their  evolution 
mottc  proprio,  but  in  the  exhibition  of  new  dynamic 
properties.  The  histological  elements,  then,  secrete,  as 
it  were,  at  the  expense  of  their  substance,  peculiar 
autogenic  excitations,  and  project  them  to  a  distance 
in  the  form  of  a  continuous  or  interrupted  current,  thus 
acquiring  a  species  of  power  of  radiating  to  a  distance 
the  vital  forces  they  have  locally  evolved. 

Thus  we  see  electric  fishes  accumulate,  in  special 
tissues  of  their  organism,  the  electric  force  which  they 
emit,  for  the  purpose  of  defence,  in  the  form  of  dis- 
charges regulated  by  a  voluntary  excitement*  Thus 
also  we  see  the  superior  animals  condense  in  the  nervous 
plexuses  of  their  organism  stores  of  motor  influence,  to 
be  distributed  through  the  peripheral  regions  in  the  form 
of  complex  manifestations  of  voluntary  motor-power,  or 
of  the  motor-power  of  vegetative  life. 

The  operations  of  automatic  activity  are,  then, 
generally  characterized  by  a  series  of  processes  inverse 
to  those  of  sensibility.  In  fact  while  the  phenomena 
of  sensibility  are  usually  characterized  by  centripetal 
currents  which  pass  from  the  peripheral  regions  where 
they  are  conceived  towards  the  nervous  centres,  the 
phenomena  of  automatic  activity,  on  the  contrary,  are 
marked  by  currents  with  a  centrifugal  direction.  With 
the  former  they  complete  the  cycle,  and  reflect  outwards 
the  excitations  which  arrive  from  the  external  world 
through  the  sensitive  regions. 

Now  if  we  consider  the  phenomena  of  automatic 
activit}^,  from  the  point  of  view  of  their  relations,  and 

*  "  De  la  substance  ^lectriciue  ou  Element  anatomique  cnracteristique  Ju 
tissue  electrogcne."     Ch,  Robin,  "Journal  de  rAnatomie,"  1.865,  p.  510. 


AUTOMATIC   ACTIVITY  OF  NERVOUS  ELEMENTS.     1 73 

their  connections  with  the  nervous  system,  we  see  that 
for  them  also,  for  the  organic  force  which  excites  them, 
the  nervous  system  similarly  plays  a  perfecting  part, 
that  it  amplifies  them,  gives  them  its  own  energy,  places 
at  their  disposal  its  conducting  filaments,  and  thus 
enables  them  to  reach  their  highest  point  of  perfec- 
tion. 

They  follow  indeed,  step  by  step,  the  progressive 
stages  of  development  of  the  nervous  apparatuses  with 
which  they  are  connected.  Thus,  in  the  peripheral 
regions  of  the  system,  where  the  phenomena  of  vege- 
tative life  take  place  by  means  of  automatic  forces 
alone,  the  nervous  elements — represented  by  the  unicel- 
lular sympathetic  ganglions,  which  are  like  so  many 
little  outposts  in  the  web  of  the  tissues — interfere  only 
occasionally  to  regulate  the  different  rhythms  of  the 
local  circulations. 

In  these  distant  regions  the  automatic  life  of  the 
individual  elements  reigns  without  contest.  It  is  local 
activity  that  rules  here  ;  and  a  sort  of  complete  decen- 
tralization characterizes  the  life  of  these  regions.* 

Little  by  little  as  we  approach  the  centres  a  progress 
towards  complete  subordination  takes  place  in  the 
distribution  of  the  living  forces  of  nervous  activity. 
Thus,  if  we  pass  from  the  ganglions  to  the  medulla,  we 
observe  that  sensitive  phenomena  are  distributed  in 
certain  regions,  and  motor  phenomena  in  others. 
Sensibility  and  automatic  activity,  which  were  vaguely 
fused  together  in  the  peripheral  ganglionic  masses,  are 

*  Unicellular  ganglions,  or  ganglions  composed  of  a  few  cells,  have  long  been 
observed  in  the  intestinal  coats,  in  the  bladder,  and  in  the  walls  of  the  vessels. 
(Legros,  "  Th^se  d'agr^gation  sur  les  nerfs  vaso-moteurs,"  Paris,  1873,  P-  i4') 


174  THE  BRAIN  AND  ITS  FUNCTIONS. 

here  distinctly  separated,  and  exercise  their  functions 
regularly  by  means  of  nervous  cell-territories  specially 
adapted  for  a  determined  end.  This  is  still  not  all  ; — 
in  the  brain  this  principle  of  the  progressive  perfection- 
ment  of  physiological  work  by  the  complexity  of  the 
apparatuses  by  which  it  is  accomplished,  becomes  more 
and  more  evident ;  so  that  automatic  activity  is  re- 
vealed not  only  in  the  phenomena  of  motor-power, 
but  also  in  the  manifestations  of  psycho-intellectual 
activity. 

Wherever,  in  fact,  the  phenomena  of  nervous  life 
are  developed,  they  appear  not  only  with  those  general 
characters  of  individual  sensibility  and  organic  phospho- 
rescence which  we  have  hitherto  recognized  as  being  the 
essential  attributes  of  every  living  nerve-cell,  but  with  a 
new  co-efficient  in  addition — that  property,  so  charac- 
teristic of  automatic  activity,  the  capacity  for  spon- 
taneous vibration,  if  their  natural  sensibility,  previously 
aroused,  be  thrown  into  agitation,  and  for  radiating  and 
projecting  to  a  distance  the  expression  of  that  histologic 
sensibility  thrown  into  agitation — at  first  in  the  form  of 
an  automatic  reaction  completely  independent  of  the 
existence  of  the  nervous  system,  and  subsequently  in 
the  form  of  nervous  discharges. 

The  automatic  activity  of  every  living  cell  is,  then, 
nothing  but  the  spontaneous  reaction  of  its  individual 
histological  sensibility,  evoked  in  some  manner  or 
another. 

This  special  form  of  the  vitality  of  the  nervous  elements 
we  are  now  about  to  consider.  We  shall  thus  see 
that  these  automatic  activities,  together  with  sensibility 
and  organic  phosphorescence,  become  the  fundamental 


AUTOMATIC  ACTIVITY  OF  NERVOUS  ELEMENTS.     1 75 

elements  of  cerebral  activity ;  that  they  associate  one 
with  another  in  a  thousand  ways,  and  combine  to  pro- 
duce the  most  complex  operations  of  cerebral  dynamics; 
and  that  they  always  underlie  most  of  the  operations  of 
cerebral  life. 


CHAPTER  II. 

GENESIS  AND    EVOLUTION    OF    AUTOMATIC    ACTIVITY, 

Spinal  Phenomena.  —  The  phenomena  of  automatic 
nervous  Hfe  reveal  themselves,  as  we  have  said,  in  their 
simplest  elementary  form  in  the  mysterious  operations 
of  vegetative  life,  while  the  sympathetic  ganglions, 
scattered  through  the  web  of  the  tissues,  and  connected 
with  the  central  regions  by  their  connective  threads, 
locally  govern  the  phenomena  of  the  local  life  of  the 
different  cell-territories,  and  act  as  little  eccentric 
centres  which  hold  in  subjection  the  purely  vegetative 
phenomena. 

In  the  centres,  in  the  purely  spinal  regions,  the  mani- 
festations of  automatic  life  again  reveal  themselves  in 
an  independent  manner,  as  though  they  had  a  special 
autonomic  character  in  each  of  the  particular  regions 
of  the  spinal  axis. 

This  automatic  activity  is  so  vivacious  in  the  minute 
structure  of  the  grey  plexuses  of  the  spinal  cord,  that 
it  persists  of  itself,  exercises  itself  motu  propriOy  apart 
from  all  participation  of  the  superior  regions  of  the 
encephalon ;  and  each  segment  of  the  cord,  considered 
as  an  independent  ganglionic  centre,  may  also,  even 
when  distinctly  isolated,  function  regularly  and  give 
rise  to  co-ordinated  reactions. 


EVOLUTION   OF   AUTOMATIC  ACTIVITY.  1 77 

In  fact,  if  we  cut  the  spinal  cord  of  living  animals 
into  separate  segments,  as  Landry  has  done,*  we  shall 
find  that  each  segment  will  isolatedly  give  rise  to  a 
series  of  independent  motor  phenomena ;  and  as  long 
as  the  blood-currents  continue  to  feed  the  cells,  and 
these  can  store  up  new  force  after  each  discharge,  and 
continue  to  live  their  morphological  life  as  before,  they 
will  continue  to  produce  nerve-force,  and  inevitably  give 
rise  to  regularly  co-ordinated  phenomena,  according  to 
previously  established  habits. 

Moreover,  the  experiments  of  Ch.  Robin,  made  upon 
the  corpse  of  a  decapitated  criminal,-f  have  shown  that 
the  automatic  activities  of  the  spinal  cord  in  man  may  in 
similar  circumstances  continue  to  exhibit  undiminished 
energy  and  power  of  co-ordination,  in  the  form  of  regu- 
larly associated  movements  with  a  definite  object  (such 
as  movements  of  defence  made  by  the  hand  after  a 
cutaneous  excitation),  performing  these  with  as  much 
regularity  as  though  the  brain  had  directed  them. 

We  have  also  true  types  of  automatic  reactions  in 
that  series  of  excito-motor  processes  which  succeed 
each  other  without  a  break  throughout  the  medtdla 
oblongata,  the  region  of  the  vital  knot,  and  in  which 
the  cells  of  this  region,  like  the  indefatigable  workmen 
of  our  great  manufactories,  work  incessantly  night  and 
day  for  the  regular  maintenance  of  the  foci  of  inner- 
vation of  the  heart  and  the  respiratory  muscles — and  this 
without  break  or  halt,  our  whole  life  long,  without  the 
intervention  of  the  conscious  personality,  and  merely 
through  the  permanence  of  the  automatic  forces. 

*  Landry,  "  Trait^  de  paralysies,"  Paris,  1859,  p.  48. 

f  Ch.  Robin,  "Journal  de  TAnatomie,"  I'aris,  1869,  p.  90. 


1/8  THE   BRAIN  AND  ITS  FUNCTIONS. 

It  is,  moreover,  a  remarkable  fact  that  this  automatic 
power  of  the  spinal  organs  is  so  great ;  its  participa- 
tion in  all  acts  that  we  primarily  accomplish  with  the 
concurrence  of  our  conscious  will  is  so  effective  and 
regular,  that  little  by  little  it  succeeds  in  gaining  ground 
in  the  domain  of  our  conscious  dynamic  operatiojis, 
obtaining  a  greater  and  greater  importance  by  means 
of  prolonged  exercise,  and  finally  ruling  over  them  more 
or  less. 

We  all  know  that  those  partial  movements  we  accom- 
plish in  tracing  written  characters,  and  in  playing 
musical  instruments,  are  at  first  executed  and  followed 
out, with  the  participation  of  the  conscious  will,  and 
that  little  by  little,  as  exercise,  as  it  were,  oils  the  auto- 
matic machinery,  this  comes  into  play  on  the  smallest 
excitement,  like  a  well-constructed  mechanical  contri- 
vance, automatically  reproducing  the  movements  learnt, 
with  a  neatness,  co-ordination,  and  correctness,  all  the 
more  perfect  because  the  conscious  personality  plays  a 
less  distinct  part  in  the  process. 

We  all  know,  more  or  less,  that  the  action  of  writing 
certain  phrases,  and  above  all  that  operation  which 
is  the  somatic  expression  of  the  conscious  person- 
ality/^r  ^;r<;^//^;^^^ — that  of  affixing  our  signature  to  a 
sheet  of  paper  (which  indicates  the  passage  of  the 
conscious  will  through  the  hand  that  expresses  it) 
insensibly  becomes  an  operation  which  escapes  our 
attention,  and  which,  like  certain  common  phrases  that 
we  unconsciously  pronounce,  takes  place  of  its  own 
accord,  simply  through  the  apposition  of  the  pen  to  the 
paper,  and  by  reason  of  the  coming  into  play  of  mere 
excito-motor  activity. 


EVOLUTION   OF  AUTOMATIC   ACTIVITY.  1 79 

We  therefore  see  what  an  enormous  part  the  phe- 
nomena of  automatism  are  called  on  to  play  in  the 
manifestations  of  nervous  life,  since  we  already  know 
that  these  not  only  regulate  the  essential  phenomena  of 
vegetative  life,  but  in  addition  play  a  most  important 
part  in  calling  into  activity  the  great  mechanism  for 
the  maintenance  of  the  human  machine,  such  as  the 
motor-power  of  the  heart  and  respiratory  apparatus — in 
a  word,  the  phenomena  of  visceral  life  ;  and  that,  more 
than  this,  they  enter  into  the  processes  of  purely  psycho- 
intellectual  life,  which  have  need  of  their  intervention 
to  project  outwards  their  extrinsic  manifestations,  and 
escape  from  the  mysterious  regions  where  they  have 
been  primitively  conceived. 


CHAPTER   III. 

AUTOMATISM   IN   PSYCHO-INTELLECTUAL  ACTIVITY* 

If,  now,  we  enter  upon  the  physiological  study  of 
cerebral  activity  proper,  we  shall  see  in  what  complex 
forms  this  curious  property  of  the  nerve-cell  reveals 
itself,  and  in  what  an  infinite  number  of  combinations 
it  is  capable  of  taking  part. 

It  is  principally  in  the  perceptive  regions  of  the 
sensoriuMy  and  those  that  are  the  seat  of  purely 
intellectual  phenomena,  that  the  manifestations  of 
intense  automatic  lite  are  most  distinct. 

In  fact,  what  takes  place  within  us  when  an  external 
impression  suddenly  thrills  us,  when  we  find  ourselves 
touched  in  the  sensitive  regions  of  our  being,  by  the 
sight  of  an  affecting  scene,  or  a  spectacle  that  charms 
us,  or  by  the  hearing  of  music  which  pleases  our  ears, 
is  this :  immediately,  by  reason  of  the  elementary 
properties  of  the  sejisorium,  which  are  at  once  called 

*  These  cerebral  phenomena  of  automatic  activity  have  been  for  the  first 
time  described  and  very  explicitly  demonstrated  by  Baillarger,  both  in  com- 
munications made  to  the  Academy  of  Medicine,  and  in  a  series  of  articles 
in  the  "  Annales  Medico-psychologiques,  "  under  the  title  of  "  Tkeoriede  I'AutO' 
matisme  et  de  I' exercice  involo7ttaire  de  la  m^moire  et  de  V imagination." 

"The  more  I  observe  lunatics,"  he  says  in  this  remarkable  work,  "the 
more  I  am  convinced  that  it  is  in  the  involuntary  exercise  of  the  faculties,  that 
we  must  seek  the  point  of  departure  of  all  form'?  of  delirium."  ("Annales 
Mcdico-psychol.,"  vol.  vi.  p.  i8S.     Idem,  1856,  p.  54.) 


PSYCHO-INTELLECTUAL  ACTIVITY.  l8l 

into  play,  sensibility  is  awakened,  and  develops  itself 
into  the  sense  of  satisfaction,  and  this  external  impres- 
sion, stored  up  in  the  vibratory  condition,  persists  in  us, 
and  becomes  a  durable  memory.  But  this  is  not  all  ; 
these  persistent  impressions,  transformed  into  durable 
memories,  do  not  remain  there  as  mere  barren  stores  ; 
the  automatic  activities  of  the  nervous  elements  which 
have  come  into  play  are  now  evoked. 

It  is,  in  fact,  as  we  have  seen,  sufficient  that  a  certain 
series  of  cerebral  cells  shall  have  simultaneously  under- 
gone a  series  of  sensorial  impressions,  in  order  that  they 
shall  form  among  themselves  a  species  of  mysterious 
association,  united  by  the  ties  of  contemporaneous  im- 
pression. If,  then,  we  happen  to  experience  any  excita- 
tion whatever,  visual,  auditory,  or  olfactory,  the  appeal 
of  the  first  in  the  series,  by  virtue  of  these  mysterious 
associations  immediately  causes  the  others  to  spring  up  ; 
former  memories  reappear,  and  so  blind  and  inevitable 
is  the  communicated  movement,  that  this  is  effected 
without  any  conscious  participation  of  the  will.  It  does 
not  depend  upon  us  to  incite  or  direct  it ;  it  follows 
its  route  by  virtue  of  its  peculiar  affinities  and  regular 
anastomoses,  as  automatically  as  the  sympathetic  and 
excito-motor  actions  that  are  propagated  through  the 
plexuses  of  the  spinal  cord. 

These  phenomena,  of  the  association  of  former 
memories  following  upon  a  recent  impression,  repeat 
themselves  at  every  instant  of  cerebral  activity.  It  is 
sufficient  for  us  to  come  fortuitously  upon  one  external 
object  to  think  of  another,  which  has  either  direct,  or 
indirect  and  artificially  maintained  relations  with  the 
former. 


1 82  THE  BRAIN   AND   ITS   FUNCTIONS. 

Reading  has  no  other  rational  basis.  It  is  the  memory 
of  the  thing  signified,  incessantly  evoked  by  the  graphic 
sign,  that  causes  us  to  adopt  automatically,  with  each 
graphic  sign  perceived  by  the  understanding,  ideas 
of  which  such  signs  are  but  the  conventional  expres- 
sion. 

In  conversation  ideas  follow  upon,  and  evoke  one 
another  in  quite  an  automatic  fashion.  We  think, 
without  wishing  it,  of  a  thing  outside  of  the  subject  in 
question,  and,  automatically,  we  are  drawn  away  from 
the  principal  thought. 

In  assemblies  we  frequently  see  certain  orators  de- 
viate by  degrees  from  the  subject  under  discussion, 
through  the  action  of  the  automatic  forces  of  their 
minds,  which  always  lead  them  in  the  direction  towards 
which  they  are  biassed — that  is  to  say,  towards  the 
regions  of  predilection,  where  their  favourite  thoughts 
have  developed  a  species  of  persistent  erethism.  These 
automatic  forces,  which  guide  human  thoughts  in  a 
certain  direction,  are  so  inevitable,  and  so  apt  to  pass 
through  a  certain  regular  orbit,  that,  the  character 
and  oratorical  habits  of  such  and  such  a  person  being 
given,  we  may  infer,  a  priori^  that  at  a  given  moment 
he  will  express  such  and  such  a  thought,  or  pronounce 
such  and  such  a  phrase. 

In  public  lectures  there  are  professors  who,  speaking 
volubly,  repeat  annually  the  same  phrases,  and  the 
same  words,  at  the  same  periods,  and  this  without  its 
being  done  voluntarily.  More  than  this  ;  it  is  notorious 
that  at  certain  examinations,  the  examiners  in  any 
given  subject  repeat  again  and  again  the  same  ques- 
tions ;  and  this  logic  of  the  automatic  cerebral  activity 


PSYCIIO-INTELLECTUAL   ACTIVITY.  1 83 

IS  so  real,  that  those  interested  have  instituted  a  course 
of  questions  designed  to  calculate  in  advance  the  auto- 
matic direction  that  the  mind  of  their  examiner  will 
follow,  and  to  anticipate  the  questions  he  will  put  to 
them. 

Every  one  knows  in  fine,  that  it  is  enough  to  set 
certain  loquacious  individuals  going  at  a  favourite  sub- 
ject, to  make  them  immediately  unfold  all  their  ideas 
upon  the  theme,  repeat  the  same  things  and  recite  the 
same  adventures,  and  this  in  a  manner  as  monotonous 
as  automatic.  Of  this  class,  old  soldiers,  huntsmen, 
and  travellers,  are  accomplished  specimens,  and  each 
of  us  may  recall  similar  examples  in  the  circle  of  his 
acquaintances. 

The  automatic  activity  of  the  cerebral  elements,  when 
it  has  been  too  strongly  over-excited,  may  reveal  itself 
in  certain  circumstances  in  a  more  intense  manner,  with 
more  vivid  colours  ;  thus  assuming  a  special  character 
without  there  being,  properly  speaking,  delirium,  since 
the  conscious  personality  still  looks  on  at  its  morbid 
condition,  like  an  involuntary  spectator. 

Thus  I  may  here  cite  a  few  fragments  of  a  letter 
written  by  a  young  man,  who  after  too  prolonged  work, 
gives  a  frank  account  of  his  impressions  and  the  auto- 
matic determination  of  his  mind  to  work,  in  spite  of 
him. 

This  young  man  had  been  for  several  days  engaged 
in  making  calculations  of  compound  interest,  which  had 
caused  a  great  tension  of  his  mind.  One  evening, 
after  dinner,  he  was  about  to  go  to  sleep,  when,  as  he 
says,  "  Without  the  slightest  encouragement  on  my 
part,  in  a  state  between  sleeping  and  waking,  waking 


£84  THE  BRAIN   AND   ITS  FUNCTIONS. 

I  may  well  say,  for  my  mind  having  worked  beyond 
its  powers  all  day,  struggled  obstinately  against  the 
corporeal  fatigue  which  strongly  incited  me  to  sleep. 
On  which  side  was  the  victory  ?  On  that  of  the  mind. 
For  without  intending  it,  and  having  need  of  the 
greatest  calm  and  repose  to  which  I  could  attain, 
/  began ^  without  the  smallest  volitioit  on  my  part,  to 
calculate  and  go  over  again  exactly  the  same  problems  as 
when  in  my  office.  The  cerebral  machine  had  been  set 
in  motion  too  violently  to  be  stopped,  and  this  involun- 
tary work  went  on  in  spite  of  me,  and  in  spite  of  and 
against  all  the  means  I  endeavoured  to  employ  to  cause 
its  cessatio7i — that  is  to  say,  from  about  three-quarters  of 
an  hour  to  an  hour  and  a  quarter." 

Commo7t  Sense.* — These  phenomena  of  automatic 
activity  are  not  only  developed  in  the  living  being,  con- 
sidered as  an  individual,  in  a  completely  unconscious 
manner,  but  besides,  by  a  species  of  diffuse  generalization, 
they  are  repeated  in  similar  individuals  in  an  identical 
manner,  and  throughout  space  and  time  provoke  in  all 
human  brains  associations  of  ideas,  and  acts  connected 
according  to  a  general  and  common  rule,  as  similar  as 
though  they  emerged  from  a  central  region  which  gave 
them  a  single  impulse. 

It  is,  in  fact,  very  curious  to  observe  that  there  are 
among  all  human  beings,  modes  of  feeling,  of  judging 
of  things,  and  of  reacting  in  consequence,  which  are 
everywhere  the  same.  Moral  phenomena,  in  fact,  occur 
in  a  manner  as  necessary  as  if  we  had  to  do  with  purely 
physical  acts. 

*  See  the  complementary  details  of  the  question  in  the  Chapter  on  the  Judg- 
ment (pp.  291,  292). 


PSYCHO-INTELLECTUAL  ACTIVITY.  1 85 

Thus,  just  as  over  all  the  surface  of  the  globe,  since 
men  have  existed,  they  move  their  forearm  in  the 
direction  of  the  articular  surfaces,  in  pronation  and 
supination,  and  bend  the  articulations  of  the  knee  and 
tlie  leg,  and  the  head,  in  an  unchangable  manner,  and  in 
a  predestined  direction — so  in  the  circle  of  ideas,  in  the 
gamut  of  sentiment,  in  the  mode  of  reacting  of  the 
human  seiisoriiim,  there  are  universal  consonances, 
which  throughout  time  and  space  present  characters  of 
eternal  immutabiJt}'. 

The  history  of  ancient  literature  shows  us  that  in  the 
same  situations  human  beings  have  always  felt,  and 
always  acted  in  an  identical  manner.  In  every  page  of 
their  tragic  or  comic  vv^orks,  we  find  that  common  fund 
of  immortal  truth  and  judicious  reflexion,  which  will  be 
eternally  current  and  applicable  at  every  epoch.  Simi- 
larly, if  we  consider  humanity  throughout  space,  we  find 
that  the  civilized  nations  of  the  extreme  East,  the 
Chinese  and  Japanese,  have  of  themselves  in  their 
long  social  evolution  automatically  invented  the  same 
processes  of  government  and  administration  which  have 
been  for  centuries  contemporaneously  employed  in  our 
old  Europe. 

Human  brains,  therefore,  everywhere  and  always 
react  in  a  common  and  identical  manner  in  presence 
of  the  external  excitations  which  impress  their  seji- 
sormm.  Each,  more  or  less,  represents  a  prism  of  the 
same  composition,  exposed  at  the  same  angle  to  the 
same  incident  rays  of  light  which  traverse  them.  Each 
undergoes  the  action  of  the  same  rays,  receives  them 
through  its  substance  in  an  identical  manner,  according 
to  a  common  proces  ,  refracts  them  in  a  similar  manner, 
14 


1 86  THE  BRAIN  AND   ITS  FUNCTIONS. 

and  disperses  them,  after  they  have  produced  in  each 
identical  phenomena  of  elementary  decomposition. 

We  thus  arrive  at  the  opinion  that  there  is  in 
humanity  a  sort  of  general  arrangement  of  ideas  and 
sentiments,  by  virtue  of  which  all  men  automatically 
take  the  same  direction  in  the  same  definite  circum- 
stances, and  judge  of  surrounding  things  in  an  identical 
manner.  It  is  this  natural  aptitude  that  we  all  possess 
for  vibrating  in  unison  with  others,  in  presence  of  an 
external  situation,  for  refracting  external  impressions 
in  a  fashion  identical  with  that  of  our  fellows,  that 
causes  us  to  have  within  us  that  notion  of  right,  accord- 
ing to  which  our  judgments  and  actions  should  be  un- 
consciously directed.  There  is,  then,  a  common  right- 
line,  a  regular  high-road  which  is,  in  a  measure,  the 
common  meridian  line  along  which  the  emotions, 
judgments,  and  actions  of  human  beings  are  directed  ; 
and  it  is  this  inner  notion,  that  we  carry  within  us,  which 
constitutes  the  rule  of  good  sense  and  common  sense. 

The  complete  man  regularly  constituted  should,  then, 
in  presence  of  fixed  determinate  emotional  situations, 
react  in  an  appropriate  manner,  make  the  same  re- 
flexions, experience  the  same  attractions,  and  the  same 
repulsions  that  his  fellows  experience.  This  is  the 
happy  point  of  contact  v/hich  unites  all  humanity  in  the 
same  joys  and  the  same  sorrows,  associates  it,  under 
whatever  latitude  and  at  whatever  epoch  we  consider  it, 
in  the  same  enthusiasms,  the  same  sympathies  and  the 
same  aversions. 

Every  theatre-goer  has  felt  himself  moved  by  the 
pathetic  situations,  and  has  associated  his  bravos  and 
his  tears  v/ith  those  of  his  neighbours.     Every  one  of 


PSYCHO-INTELLECTUAL  ACTIVITY.  187 

US  in  solemn  moments  of  the  national  life,  has  felt 
himself  thrilled  by  the  general  excitement  caused  by 
those  poignant  patriotic  emotions  that  the  men  of  our 
generation  have  experienced  in  sorrowful  alternation. 
Every  one  who  stood  upon  the  Boulevards  of  Paris  in 
1S59,  when  the  French  army  marched  past,  returning 
from  the  campaign  of  Italy,  must  have  participated 
with  all  his  heart  in  the  general  intoxication  of  victory ; 
and  every  one  who  stood  on  those  same  Boulevards  a 
few  years  after,  among  anxious  and  over-excited  crowds, 
when  all  our  disasters  were  announced,  must  have  felt 
all  hearts  beat  in  unison  with  his  own,  and  his  secret 
borrows  reflected  in  all  faces. 

Comumnication  of  Automatic  Activity  to  others. — 
Automatic  activity  works  in  human  brains  according  to 
laws  so  inevitable  and  energies  so  involuntary,  that  we 
may  count  upon  it  at  a  given  moment,  consider  it  as  a 
livinsf  force  in  the  static  condition,  and  excite  it  without 
the  agency  of  volition,  as  we  see,  for  instance,  bodies 
electrified  in  a  certain  manner  act  at  a  distance  upon 
neighbouring  bodies,  and  modify  the  dynamic  conditions 
of  the  electric  forces  latent  in  them. 

The  cerebral  automatic  activity  develops  itselt  also 
at  a  distance,  passing  from  one  individuality  to  another 
by  the  intervention  either  of  speech,  writing,  or  gestures, 
which  excite  the  sensor imn  of  the  individual  addressed  ; 
and  the  excitement,  once  communicated,  is  propagated 
from  point  to  point,  through  the  plexuses  of  the  cortex 
in  a  continuous  manner,  by  the  mere  automatic  forces 
of  the  nervous  elements,  which  disengage  their  latent 
energies. 

Thus  it  is  that  human  speech  provokes  in  the  soi^ 


l88  THE  BRAIN  AND   ITS   FUNCTIONS. 

soriiun  of  any  one  who  hears  it  involuntary  reflexions, 
which  traverse  the  brain,  and  finally  produce  a  unison 
between  him  who  hears  and  him  who  speaks.  The  art 
of  persuasion  has  no  other  physiological  raison  d'etre 
than  the  setting  in  vibration  of  the  sensitive  cords  of  the 
emotional  regions  of  the  scnsoviuni,  and  the  direct  or 
indirect  neutralization  of  previous  prejudices.  It  is  by 
this  process  that  the  act  of  causing  laughter  at  the 
proper  time,  and  of  turning  aside  the  attention  by 
exciting  unexpected  sentiments  is  often  a  means  of 
disarming  one's  judges. 

It  is  by  setting  in  motion  the  automatic  forces  latent 
in  human  brains,  that  great  orators  get  possession  of 
an  attentive  audience,  subjugate  it,  and  excite  in  it 
involuntary  ecstasies  of  emotion  and  enthusiasm  ;  that 
great  writers  develop  a  whole  series  of  unconscious 
emotions  through  which  their  moving  recitals  hold  us 
spell-bound  ;  that  a  word  or  a  phrase  evokes  a  whole 
series  of  involuntary  ideas,  which  give  rise  to  a  crowd  of 
reflexions  and  emotions,  corresponding  to  those  they 
wish  to  inspire  in  us.  It  is  by  virtue  of  the  same 
general  laws  of  communicated  emotion  that  the  perio- 
dical publications  of  the  press,  by  daily  percolating 
through  the  minds  of  their  readers,  give  an  automatic 
direction  to  their  ideas  (human  laziness  being  so  fond  of 
ready-made  phrases;,  and  produce  in  those  who  enjoy 
them  that  fixed  mental  direction  they  unconsciously 
acquire. 

The  same  automatic  tendencies  of  the  human  mind 
to  provoke  co-ordinated  associations  of  ideas,  thoughts 
and  emotions,  connected  with  other  thoughts  and  emo- 
tions by  the  mysterious  links  of  former  relationship,  are 


PSVCIIO-INTELLECTUAL  ACTIVITY.  1 89 

visible  in  every-day  life,  and,  by  means  of  words  of 
double  meaning — transparent  allusions,  which,  in  connec- 
tion with  one  word,  make  us  think  of  other  words — 
produce  the  most  unexpected  effects,  and  the  most 
unforeseen  mental  suggestions. 

People,  in  fact,  who  in  their  conversation  handle 
double  meanings  with  art,  know  very  well  that,  by 
underlining  a  word,  by  an  inflexion  of  the  voice,  a  look, 
a  gesture,  they  will  awake  in  the  minds  of  their  audience 
a  series  of  ideas  and  emotions  of  a  nature  different 
from  that  indicated  by  their  words.  The  simple  phrase 
of  allusion,  when  perceiv^ed  in  the  brain  in  the  form 
of  a  phonetic  impression,  follows,  as  it  were,  two 
parallel  routes — one  natural,  apparent,  traced  by  the 
word  itself;  the  other  roundabout,  divergent,  traced 
by  the  intonation  and  gesture.  There  result  thus 
from  these  simultaneous  processes,  which  are  propa- 
gated through  the  cerebral  tissue,  various  series  of 
unconscious  reactions,  which,  in  the  form  of  memories, 
associated  ideas,  and  different  sentiments,  are  succes- 
sively awakened.  Hence  the  unexpected,  vivid,  and 
piquant  relations  between  certain  ideas  that  provoke 
hilarity,  and  certain  distant  thoughts  which  may  cause 
the  fibres  of  our  inner  emotivity  to  vibrate  in  a  more 
or  less  indirect  manner. 

What  more  simple,  apparently,  than  to  speak  of  a 
cradle  to  a  young  girl,  and  yet  what  more  cutting,  since 
one  is  sure  to  see  her  sensibility  in  agitation  betray 
itself  by  the  blush  of  modesty .? 

A  vulgar  proverb,  in  the  same  circle  of  ideas,  says 
that  "  We  must  not  speak  of  a  rope  in  the  house  of  one 
who  has  been  hung." 


190  THE   BRAIN   AND   ITS   FUNCTIONS. 

The  ancients,  at  the  door  of  the  hipanars,  used  to 
inscribe  these  words :  **  Cave  canem,"  etc.,  etc. 

It  is  in  these  processes,  which  plunge  as  it  were 
by  multiple  roots  into  the  fruitful  stores  of  our 
memories  and  emotions,  present  and  past,  that  dra- 
matic literature  finds  its  most  powerful  machinery. 
How  many  pathetic,  and,  more  often  still,  how 
many  comic,  scenes  are  produced  by  nothing  but  the 
apparent  contrast  between  the  visible  situation  of  the 
personages  on  the  stage  and  the  gestures  and  intona- 
tions of  the  actors,  which  appeal  to  quite  another  genus 
of  ideas,  thus  automatically  provoking,  by  this  very 
fact,  bursts  of  laughter  or  movements  of  terror — even 
in  situations  which  are  apparently  far  from  inspiring 
gaiety  or  terror. 

It  is  always  the  automatic  activity  of  the  cerebral 
elements  that  comes  into  play  in  those  different  con- 
ditions, provoked  in  the  sensoriuin  by  means  of  plays 
on  words  and  certain  well-made  puns. 

It  is,  in  fact,  in  consequence  of  the  unexpected  asso- 
ciation of  two  opposite  ideas  that  the  hilarious  paroxysm 
is  produced  in  us.* 

Reflexion  of  Automatic  Activity. — One  of  the  most 
interesting  facts  as  regards  the  phenomena  of  auto- 
matic activity  is  this  :  that  they  are  not  only  maintained 

*  In  certain  morbid  forms  of  cerebral  activity  this  automatic  tendency  no 
longer  reveals  itself  (as  regards  opposite  ideas  suddenly  associated)  by  similar 
words.  It  is  by  smiple  assonances  which  appeal  one  to  another  and  group 
themselves  together  automatically.  Thus  a  patient,  described  by  Parehappe, 
with  great  mental  volubility,  often  in  her  speech  formed  associations  of  ideas  after 
this  fashion.  "On  dit  que  la  Vierge  estfoUe,  on  parle  de  la  Her,  ce  qui  ne  fait 
pas  les  affaires  du  departement  de  I' Allier.^'  On  being  told  to  make  charpieshe 
said  that  she  did  not  know  how.  ^  his  was  insisted  on,  the  physician  adding  ; 
'*  ]t  \oViS  <ii\s  d' en /aire."     She  answered  :  "  II  ne  fait  pas  bon  dans /V;//fji-." 


PSYCHO-INTELLECTUAL  ACTIVITY.  I9I 

by  means  of  the  incessant  influx  of  excitations  which 
come  from  the  external  world,  impinge  upon  the  sen- 
svriiun,  and  demand  its  active  participation,  but  that, 
ill  addition,  they  reveal  themselves  of  their  own  accord, 
old  memories  forming  in  us,  as  it  were,  so  many 
autogenic  foci,  which  kindle  themselves.  From  this 
it  results  that,  by  means  of  this  prolongation  of  former 
excitations,  automatic  activity  feeds  itself,  maintains 
itself  locally,  and  develops  itself  in  the  form  of  medita- 
tion and  reflexion  at  the  expense  of  the  stores  accumu- 
lated in  the  past,  which  thus  become  the  aliments  of  its 
incessant  activity. 

We  all  know  that,  when  we  have  to  come  to  a 
resolution,  we  have,  as  it  is  said,  need  for  reflection, 
for  maturing  it  in  our  mind  ;  that  is  to  say,  must 
give  it  up  to  the  automatic  activity  of  our  mind,  which 
takes  possession  of  it,  reacts  in  consequence,  and  causes 
new  ideas,  unexpected  thoughts,  unforeseen  points  of 
sight,  which  give  it  more  weight,  to  arise.  Night,  it  is 
said,  brings  counsel ;  that  is  to  say,  in  consequence  of 
simple  repose  the  cerebral  elements  have  recovered  their 
proper  vitality,  and  have  become  more  fit  to  develop 
their  natural  energies  in  presence  of  the  resolution 
in  question.  Thus  it  is  that  the  automatic  forces  of  the 
brain,  concentrated  around  a  circle  of  definite  ideas, 
develop  themselves  automatically,  provoke  the  inter- 
vention of  new  elements,  and  finally  create  quite  new 
methods  of  seeing  and  considering  things.  And  what 
is  well  worth  attention  is  that  all  this  series  of  mar- 
vellous phenomena  develops  itself  motu  proprio,  and 
outside  of  the  conscious  personality,  which  looks  on  at 
this  subtle  work,  and  is  as  powerless  to  excite  it  when 


192  THE  BRAIN   AND   ITS  FUNCTIONS. 

it  slackens,  as  to  restrain  it  when  it  is  developed  in 
excess  ! 

Aiitomatism  in  the  Sphere  of  the  Psychic  Activity 
Proper. — The  automatic  energies  of  the  cerebral  ele- 
ments, as  we  have  just  seen,  play  a  principal  part  in  the 
processes  of  sensorial  perception,  as  in  those  of  intel- 
lectual activity  proper.  If  we  now  pass  to  the  examination 
of  the  phenomena  of  purely  psychical  activity — that  is 
to  say,  of  those  which  are  characterized  by  moral  sen- 
sibility and  emotivity — it  is  not  without  surprise  that 
we  see  that  these  same  automatic  vital  forces  reveal 
themselves  here  also  with  clearly  distinguished  cha- 
racters, and  that  while  always  active,  alv/ays  identical, 
under  the  most  diverse  forms — either  under  the  name 
of  involuntary  temptation,  irresistible  impulse,  etc.,  they 
alw^ays  betray  the  inner  secrets  of  the  emotional  regions 
of  the  sensoriicm  where  they  have  originated,  even  in 
presence  of  the  conscious  will,  which  is  powerless  to 
regulate  their  manifestations.* 

The  labour  of  life  is  an  incessant  struggle  between 
the  acts  of  conscious  volition  and  the  automatic  impulses 
of  the  emotional  regions  of  our  being.  Ordinary  lan- 
guage is  rich  in  metaphors  which  express  in  appropriate 
forms  what  is  unalterable  and  inevitable  in  this  special 
domain  of  our  mental  activity.  These  phrases :  im- 
pulses, cntJuisiasms  of  the  hearty  sentiviental  biases, 
spontaneous  otctbiirsts  of  tenderness,  are  trite  and  even 
silly  expressions  by  which  we  have  always  expressed 
those  manifestations  of  our  sensitive  nature,  in  which 

*  Emotional  sensibility  develops  itself  so  involuntarily,  that  in  the  theatre, 
even  when  we  know  that  all  that  is  there  represented  is  but  fiction,  the 
simple  sight  or  he.irmg  of  pathetic  scenes  suffices  to  set  our  restrained  sen^-i- 
Lility  in  vibration,  and  spiie  of  us  causes  our  tears  to  flow. 


PSYCHO-INTELLECTUAL  ACTIVITY.  1 93 

there  is  an  involuntary  and  unconquerable  element. 
There  are  many  persons  to  whom  we  feel  ourselves 
involuntarily  drawn  by  the  captivations  of  their  person- 
ality, and  many  others  who,  on  the  contrary,  drive  us 
away  by  a  sort  of  repulsive  radiation  that  they  project 
to  a  distance.  How  often  in  the  gamut  of  tender 
sentiments  a  single  look  has  sufficed  to  throw  the  whole 
being  into  commotion,  and  to  excite  all  the  sensitive 
fibres !  How  often,  in  contrary  circumstances,  a  mena- 
cing and  imperious  glance  has  sufficed  to  strike  the 
individuals  upon  whom  it  has  been  darted,  as  with  a 
thunderbolt,  and  fix  them  immovably  to  the  spot ! 
We  know,  indeed,  that  both  love  and  hatred,  from 
the  very  fact  that  they  express  different  conditions  of 
our  sensorhtm  in  agitation,  are  quite  automatic  and 
unconscious  sentiments.  They  are  inspired  and  expe- 
rienced, not  commanded  by  the  intervention  of  the 
human  personality. 

And  it  is  remarkable  that,  just  as  in  the  sphere  of  in- 
tellectual phenomena  there  is  a  necessary  logical  order 
according  to  which  they  succeed  one  another,  so  there 
is  similarly  a  logic  of  sentiments  and  passions  which 
imposes  itself  on  ,this  series  of  purely  moral  phenomena 
of  the  natural  sensibility,  and  which,  at  a  given  moment, 
follows  its  regular  course  in  the  heart  of  man,  liKe  the 
series  of  ideas  which  are  logically  connected  in  his 
mind. 

It  is  more  or  less  profound  knowledge  of  these  spon- 
taneous reactions  of  the  human  sensibility  in  presence 
of  such  a  given  circumstance,  that  enables  great  writers 
to  know  point  by  point,  and  express  with  precision,  and 
put  into  the  mouths  of  their  personages,  natural  expres- 


194  THE   BRAIN  AND   ITS   FUNCTIONS. 

sions  of  the  passions  which  are  to  be  developed  in  them. 
It  is  because  there  is  a  logical  order  in  the  evolution  of 
the  sentiments  and  passions,  that  we  can  a  priori  infer 
the  effects  produced  upon  our  fellows  by  a  good  and 
happy  piece  of  news,  and  know — ^judging  by  ourselves, 
and  representing  to  ourselves  what  we  should  feel  in  like 
circumstances — in  what  manner  their  sensibility  will  be 
touched,  or  what  emotions  they  will  naturally  expe- 
rience. 


CHAPTER   IV. 

DREAMS. 

The  automatic  activity  of  the  cerebral  cells  reveals 
itself  also,  in  a  very  distinct  manner,  at  night  in  the 
form  of  persistent  impressions — dreams.  It  naturally 
follows,  from  what  we  have  already  explained,  that, 
in  reality,  dreams  are  nothing  but  the  persistent  vibra- 
tion of  certain  groups  of  cells  in  a  condition  of  erethism, 
when  the  greater  number  of  their  fellows  are  alreadv 
plunged  into  the  collapse  of  sleep. 

This  persistent  vibration  of  the  nervous  elements 
may  be  explained  physiologically,  either  by  the  fact  of 
a  strong  super-excitation  occurring  in  consequence  of 
too  prolonged  exercise,  or  because  of  some  special  ex- 
citability, some  peculiar  receptive  condition  of  certain 
cell-territories,  which  have  felt  external  stimulations  more 
intensely  than  tjie  neighbouring  regions.  It  is,  then, 
sufficient  that  a  certain  number  of  them  shall  continue 
in  vibration,  in  order  that  these  shall  become  centres  of 
appeal  for  other  agglomerations  of  cells  with  which 
they  have  either  more  intimate  affinities,  or  more  or  less 
facility  of  anastomosis.  Hence  arises  a  series  of  revivals 
of  past  impressions,  of  which  we  scarcely  catch  the 
sense,  but  which  have  secret  connexions  one  with 
another  (unconscious  memory)  ;  a  series  of  unex- 
pected and  disorderly  ideas,  which  follow  one  another 


196  THE  BRAIN    AND  ITS   FUNCTIONS. 

in  the  strangest  forms.  They  are  developed  by  the 
mere  automatic  forces  of  the  cerebral  cells  abandoned 
to  their  own  will,  and  freed  from  the  directing  in- 
fluence of  sensorial  impressions  (visual  impressions), 
which,  in  the  natural  order  of  things,  keep  them  awake 
and  regulate  their  diurnal  mode  of  activity.*  Hence 
those  unexpected  apparitions  which  surprise  us  in  dreams, 
and  which  are  nothing  but  the  result  of  the  partial 
awakening  of  certain  cells,  which  thus  cause  a  series  of 
long- forgotten  impressions  to  rise  again  in  the  scft- 
sorium.  These,  however,  are  in  reality  never  anything 
but  impressions  which  make  a  part  of  the  stores  we 
have  acquired,  which  reveal  themselves  in  our  dreams, 
and  which,  probably  under  the  influence  of  local  condi- 
tions of  circulation,  neighbouring  impressions,  &c.,  re- 
vive from  out  the  depths  of  our  past.  To  dream  of 
anything,  we  must  have  seen  it  in  one  fashion  or  another. 
It  is  not  rare,  in  seeking  out  the  origin  of  certain  dreams, 
to  recognize  that  a  great  number  have  a  more  or  less 
direct  relation  to  an  impression  that  was  more  or  less 
strongly  impressed  upon  us  in  the  waking  state,  and 
that  they  are  but  a  species  of  echo  of  this  impression, 
associated  with  more  or  less  heterogeneous  impressions.-j- 

*  The  direct  influence  of  the  arrival  of  sensorial  influences,  and  visual  in 
particular,  on  the  regularity  of  the  play  of  the  cerebral  cells,  is  such  that  in  a 
patient,  whose  case  is  reported  by  Baillarger,  in  a  waking  condition  it  was 
sufficient  to  lower  his  eyelids  and  thus  suppress  the  arrival  of  optic  impressions 
in  his  brain,  to  cause  apparitions  of  various  objects,  of  which  he  had  previously 
no  idea,  to  appear  to  him  immediately;  and  this  by  means  of  the  mere  auto- 
matic forces  of  the  brain,  which  resumed  their  course,  inotu  propria,  when 
external  impressions  were  excluded.  ("Annales  Medico-psychoL,"  vol.  vi, 
p.  178.) 

■f  A  young  girl,  mentioned  by  Prus,  believed  she  had  merited  eternal  punish- 
ment by  having  given  way  to  too  tender  a  sentiment.     This  idea  preoccupied 


DREAMS.  197 

Hence,  again,  those  curious  phenomena  through  which 
dreams  produce  in  us  subsequent  emotions  which  so  pro- 
foundly overwhelm  us. 

These  emotions,  as  we  have  said,  are  necessarily  asso- 
ciated with  the  former  impressions  which  have  given 
them  birth.  They  live  with  the  same  life,  so  that  the 
appeal  of  the  former  inevitably  evokes  its  fellow.  If 
the  first  sight  of  any  person,  or  spectacle,  or  scene, 
have  caused  us  a  moment  of  pleasure  or  anxiety, 
the  reminiscence  evoked  by  the  same  objects  will  be 
followed  by  the  same  emotions  of  our  natural  sensibility. 
In  the  domain  of  dreams  the  same  phenomena  unfold 
themselves  in  the  same  concatenation  ;  if  one  idea  or 
agreeable  memory  arise  in  Uie  psychical  sphere,  in  con- 
sequence of  a  state  of  erethism  in  a  special  region  of 
the  brain,  immediately  an  analogous  condition  of  con- 
comitant satisfaction  will  be  felt  in  the  sensormm — if  an 
idea  of  quite  another  nature  should  arise,  either  spon- 
taneously or  through  some  disturbance  occurring  in  the 
visceral  innervation  (cardiac  anxiety,  gastric  pain,  irrita- 
tion of  the  genital  organs)  ;  if  the  mind,  for  instance, 
gives  birth  to  conceptions  regarding  precipices,  scenes 
of  murder,  etc. ;  at  the  same  time  analogous  states  are 
developed  in  the  emotional  regions  of  our  organism, 
and  this  artificial  evocation  of  sensibility  may  pro- 
duce a  shock — a  dynamic  effect — intense  and  power- 
ful enough  to  awaken  the  sleeping  cerebral  cells.  Thus 
it  is  always  the  mere  automatic  forces  of  the  nervous 
elements    which    regulate    and    govern    the    world    of 

her  vividly  for  some  time,  until  she  believed  one  night  that  she  saw  and  heard 
a  ri'essenger  from  heaven  who  announced  her  eternal  damnation  and  that  of 
her  family.     ("Annales  Mddico-psycholo^^.,"  vol.  iii.  p.  103.) 


198  THE   BRAIN   AND   ITS   FUNCTIONS. 

our    thoughts    and    sentiments,    sleeping    as    well    a 
waking. 

This  invincible  persistence  of  the  activity  of  the  cere- 
bral cells  reveals  itself  very  clearly  in  the  following 
circumstances.  Just  as  the  phenomena  of  their  diurnal 
encroach  upon  those  of  their  nocturnal  activity,  so,  in- 
versely, we  often  see  those  of  their  nocturnal  activity 
perpetuated  while  we  lie  awake  or  are  dreaming,  and 
not  ceasing  even  at  the  moment  of  total  awaking  of  the 
brain. 

We  all  know  that  when  we  awake  we  may,  for  a 
while,  generally  in  the  early  morning,  preserve  the  re- 
membrance of  the  dreams  that  have  traversed  our  brain 
during  the  night.  We  have  all  met  with  a  certain 
number  of  persons  who  are  more  or  less  intensely 
pre-occupied  with  the  dreams  that  have  assailed  them. 
Certain  feeble  characters  are  even  more  or  less  depressed 
by  them,  and  preserve  a  painful  impression,  which  they 
sometimes  consider  a  true  presentiment  of  what  may 
happen  to  them. 

It  is,  however,  in  certain  forms  of  mental  maladies 
that  this  power  of  dreams  to  persist  during  waking 
moments  acquires  the  greatest  degree  of  intensity. 
Thus  we  see  a  certain  number  of  patients,  paralytics,  or 
victims  of  hallucination,  change  the  character  of  their 
delirious  conceptions  and  take  up  new  ideas,  which  are 
nothing  but  persistent  dreams  that  have  been  suddenly 
developed  in  their  minds  at  night.  Thus  when  I  fnivl 
patients  expressing  certain  ideas  and  certain  appre- 
hensions in  the  morning,  I  infer  that  they  have  had 
terrifying  impressions  of  a  certain  kind,  and  should 
expect  to   see  this  emotional   condition   persist  in  the 


DREAMS.  199 

form  in  which  it  was  implanted  until  it  became  a  fixed 
and  permanent  idea,  a  delirious  conception  of  new 
formation.  We  must,  therefore,  seek  the  origin  of  the 
transformation  of  certain  deliriums,  and  certain  ideas 
which  unexpectedly  change  the  direction  of  the  mental 
state  of  certain  individuals,  in  the  continuation  of  the 
period  of  erethism  of  certain  groups  of  cerebral  ceils, 
which  have  come  into  action  during  the  period  of  sleep, 
and  continue  to  vibrate  even  during  the  waking  con- 
ditioii. 


CHAPTER  V. 

DEVELOPMENT   OF  AUTOMATIC  ACTIVITY. 

The  automatic  activity  of  the  nervous  elements  awakes 
at  variable  epochs,  according  to  the  precocity  of  mor- 
phological development  of  these  elements.  Thus,  the 
spinal  axis  being  more  rapidly  developed  than  the 
brain,  in  the  regular  evolution  of  the  nervous  system, 
automatic  manifestations  may  take  place  in  it,*  even 
while  they  are  very  imperfectly  developed  in  the  cerebral 
grey  substance. 

The  manifestations  of  automatic  activity  in  the  brain 
follow  by  degrees  the  progress  of  physical  develop- 
ment, and  this  in  a  very  rapid  fashion.  When  the 
arrival  of  external  excitations  calls  its  sensibility  into 
play  in  the  different  foci  in  which  it  is  concentrated, 
the  child  begins  to  benefit  by  the  automatic  develop- 
ment of  the  activity  of  his  cerebral  instrument,  and 
it  is  by  this  process  of  continual  absorption  of  impres- 
sions, which  incessantly  reverberate  in  all  the  regions 
of  the  scnsoriiwiy  that  the  external  world  penetrates  into 
him,  and  that  by  the  silent  evolution  of  the  specific 
energies  of  the  cerebral  cells,  his  mental  development 
goes  on  with  that  prodigious  rapidity  which  excites  our 
astonishment. 

We  have  all  witnessed  and  wondered   at  the  inces* 


DEVELOPMENT   OF   AUTOMATIC   ACTIVITY.       201 

sant  mobility  of  these  young  creatures,  and  their 
insatiable  appetite  for  knowledge  of  the  external  world. 
They  want  to  embrace  it  with  their  little  hands,  to 
touch  all  that  surrounds  them,  and  take  cognizance  of 
ever}^thing  that  comes  within  their  ken.  We  have 
been  struck  by  their  deep  reflections,  of  which  the 
scope,  the  logic,  and  the  subtlety,  surprise  us  all  the 
more  from  their  being  exempt  from  all  reserve,  and 
their  coming  to  light  simply  from  the  natural  play  of 
the  cerebral  activity  abandoned  to  its  frankest  mani- 
festations. 

Moreover,  while  the  physical  world  penetrates  into 
him  and  leaves  its  traces  upon  him,  the  child  begins  to 
feel  emotions,  and  have  developed  in  him  the  primordial 
elements  of  common  sensibility.  He  feels  very  distinctly, 
of  his  own  accord  and  by  the  mere  energies  of  the 
vitality  of  his  own  sensoriiini,  what  things  and  persons 
are  agreeable  or  disagreeable  to  him. 

It  is  through  the  action  of  the  same  unconscious  vital 
forces  that  his  first  sentiments  arise,  and  are  developed 
and  perpetuated  ;  by  means  of  a  blind  original  force, 
without  the  direct  intervention  of  the  personality. 

Childhood  and  youth  are  the  two  phases  of  life 
during  which  the  automatic  activity  of  the  cerebral 
elements  reveals  itself  with  the  greatest  energy.  It  is 
the  period  when  memory  has  the  greatest  vigour,  when 
the  sensibility  of  the  cerebral  cell  is  most  exquisite, 
either  to  feel  the  excitations  which  thrill  through  it,  or 
to  retain  them.  It  is  also  that  at  which  its  reactionary 
faculties  are  most  intense. 

It  is  indeed  the  period  when  ideas  are  associated  with 
the  greatest  rapidity,  when  the  conjunction  of  new  with 

15 


202  THE  BRx\IN  AND   ITS   FUNCTIONS. 

old  ideas  takes  place  instantaneously,  when  individual 
spontaneity  and  personal  originality  burst  forth  in  the 
most  pronounced  manner,  and  when,  in  fact,  the  man 
appears  with  the  cerebral  temperament  which  specifi- 
cally characterizes  him. 

As  maturity  approaches,  the  automatic  energies  of 
the  cells  become  gradually  less  intense.  Their  sensibility 
is  already  dulled  in  consequence  of  the  multitude  of 
impressions  which  have  affected  them  in  turn  ;  their 
appetite  for  unknown  things  is  less  intense ;  it  is  their 
period  of  beginning  saturation.  The  thirst  for  know- 
ing and  registering  new  facts  calms  down  by  degrees, 
and  the  mental  forces  then  concentrate  themselves  for 
the,regular  classification  of  acquired  riches,  the  methodic 
grouping  of  facts  belonging  to  the  past,  and  the  calling 
into  activity  of  the  materials  long  ago  accumulated, 
which  serve  for  the  building  up  of  our  judgments,  the 
formation  of  our  thoughts,  the  maturation  of  our  re- 
flections— so  that  if  the  human  brain  has  already  lost 
something  of  its  freshness,  and  the  juvenility  of  its 
manner  of  feeling,  it  has  gained,  per  contra,  the  fruits 
of  acquired  experience.  It  knows  and  automatically 
expresses  what  it  knows  ;  and  these  different  modes 
in  which  the  human  personality  reveals  itself  as  regards 
its  external  manifestations,  represent  the  true  synthesis 
of  all    the   mental  activities   in   their   full  expansion* 

*  It  is  curious  to  observe  practically,  in  every-day  life,  how  variable  the 
degree  of  the  automatic  energies  is  in  dilferent  individuals,  as  regards  the 
rapidity  of  the  transmission  of  nervous  excitations  to  the  brain  and  of  the  con- 
secutive reactions.  We  know  indeed  how  many  individuals  there  are  who,  as 
it  is  said,  have  their  understandings  slow,  sluggish,  and  hardly  permeable  by 
the  stimulations  of  ihe  external  world,  which  are  radiated  towards  them. 
Every  one  knows  that  a  great  number  of  people  exist,  who,  although  very 
iutelliiient  as  regards  a  certain  class  of  ideas,  are  incapable  of  appreciating  the 


DEVELOPMENT  OF  AUTOMATIC  ACTIVITY.       203 

The  effects  of  progressive  senilit}'  are  marked  by  in- 
sensible gradations  in  human  brains,  by  a  slow  and 
gradual  enfeebling  of  the  automatic  activity  of  their 
elements. 

That  failure  of  appetite  for,  and  curiosity  about,  new- 
things,  which  is  already  marked  in  the  preceding  stage, 
becomes  more  and  more  distinct  That  deadening  of  the 
sensibility,  which  expresses  the  complete  saturation  of 
the  elements  of  the  sensoriuin  and  their  incapacity  for 
maintaining  a  condition  of  erethism,  takes  more  and 
more  significant  forms.  The  human  brain  experiences 
the  need  of  prolonged  repose ;  the  ardour  of  the  grand 
struggle  for  life  becomes  painful  to  it.  A  retreat  is 
sounded  from  a  great  number  of  social  careers.  Thus 
it  is  that  that  period  of  inactivity  which  inevitably 
awaits  each  individual,  as  regards  the  social  part  he  has 
played,  physiologically  expresses  the  slow  and  gradual 
wearing  out  of  the  energies  of  automatic  life,  which 
by  degrees  cease  to  vibrate,  and  betray  by  their  slacken- 
ing the  progressive  dulling  of  the  sensibility  of  the 
cerebral  cell. 

In  proportion,  then,  as  sensibility  grows  languid,  and 
the  faculty  of  erethism  loses  its  energy  in  the  elements 
of  the  sensormnZy  the  external  manifestations  of  the  life 
of  the  brain  undergo  a  parallel  retrogressive  movement. 
Repose  and  silence  insensibly  invade  them.  The  field  of 
the  ideas  and  sentiments  grows  narrower ;  intellectual 
spontaneity  becomes  languid,  and  verbal  expression,  and 

n<=sociation  of  two  incongruous  ones.  They  but  very  slowly  comprehend 
facetiae  and  plays  upon  words,  and  in  conversation,  when  a  play  upon  words 
has  been  made  and  every  one  has  laughed,  they  alone  hang  fire,  and  show 
by  a  tardy  burst  of  laughter  that  the  hilarious  effect  has  at  last  been  produced 
upon  them  also. 


204  THE  BRAIN  AND   ITS   FUNCTIONS. 

conversation,  dried  up  at  the  fountain-head,  cease  to  be 
interesting  and  endowed  with  a  spontaneous  character. 
The  man  who  has  nothing  to  say,  who  has  but  a  few 
notes  of  his  personality  to  set  vibrating,  speaks  no  more 
or  says  but  little,  at  least  if  we  do  not  take  for  original 
conversation  those  vapid  phrases  that  men  think  them- 
selves obliged  to  exchange,  when  they  are  in  each  other's 
company,  and  of  which  the  inanity,  to  some  extent 
reflex,  only  covers  the  absence  of  ideas  and  sentiments. 

Thus  it  is  that,  through  the  necessary  connections 
which  unite  all  the  zones  of  cerebral  activity,  the  mani- 
festations of  senility  by  degrees  gain  ground  in  the 
psycho-intellectual  spheres.  The  mere  fact  that  there 
are  regions  of  the  brain  which  have  primarily  been 
struck  with  stupor  and  histological  degeneration,  causes 
the  same  retrogressive  processes  to  radiate  to  a  distance^ 
and,  through  secondary  lesions,  inevitably  to  produce 
the  symptoms  of  senility  and  more  or  less  progressive 
dementia. 


CHAPTER  VI. 

FUNCTIONAL    PERTURBATIONS     OF    AUTOMATIC 

ACTIVITY. 

It  is  in  the  series  of  morbid  phenomena  pecuh'ar  to 
mental  diseases  that  the  processes  of  automatic  activity 
generally  present  themselves  with  their  most  signifi- 
cant characters  of  intensity,  and  in  the  most  diverse 
forms. 

It  is,  in  fact,  the  automatic  activity  of  the  cerebral  cell 
that  always  more  or  less  comes  into  play,  in  general  or 
partial  delirium,  and  in  irresistible  impulse,  being  every- 
where essentially  active,  and  everywhere  present.  It  is 
always  this  that  reveals  itself  with  those  characters  of 
irresistibility,  and  that  evident  freedom  from  voluntar}^ 
action  which  are  its  special  characteristics. 

Thus  general  delirium,  with  that  exuberance  of 
thoughts  which  clash  and  associate  in  the  most  unex- 
pected manner  in  the  brain  of  the  patient,  is  the  highest 
expression  of  the  automatic  activity  of  the  cerebral 
cells  in  a  condition  of  irrepressible  erethism.  It  is 
enough  to  have  seen  patients  at  this  period  of  extreme 
over-excitement,  to  recognize  the  fact  that  the  will 
is  powerless  to  repress  the  disorder ;  that  the  very 
elements  that  constitute  human  personality  are  them- 
selves  in    disarray  ;    and    that  in  this   agitation    these 


206  THE  BRAIN   AND   ITS  FUNCTIONS. 

incoherent  words,  these  sonorous  explosions  to  which 
all  the  cerebral  elements  contribute  in  so  unconscious 
a  manner,  we  cannot  fail  to  recognize  the  tumultuous 
expression  of  the  forces  of  normal  energy,  unchained 
and  hurried  into  a  very  whirlwind  of  morbid  over- 
activity. 

In  some  forms  of  partial  delirium,  we  see  patients 
less  vehemently  hurried  along  in  spite  of  themselves  ; 
incessantly  delirious  on  certain  points,  conceiving 
the  same  delirious  conceptions,  always  repeating  the 
same  phrases,  without  perceiving  that  their  ideas  are  in 
complete  discord  with  reality.  Thus  they  say  they  are 
ruined,  robbed  by  every  one,  poisoned  ;  and  even  if 
anyone  should  reason  with  them,  proof  in  hand,  re- 
specting the  folly  of  their  apprehensions,  and  reassure 
them  in  a  thousand  ways,  the  automatic  activities  of 
their  brain  are  so  set  in  a  false  direction  that  they 
incessantly  return  to  it,  just  as  a  contracted  member  on 
being  extended  will  resume  its  former  position.  They 
are  perpetually  complaining,  they  incessantly  repeat 
the  same  phrases,  the  same  vague  apprehensions,  and 
unconsciously  fall  back  into  the  same  ruts  followed 
without  conviction,  without  participation  of  their  con- 
scious personal'ty,  merely  by  dint  of  the  automatic  forces 
of  their  troubled  mind.* 

In  other  circumstances  automatic  activity  is  exercised 
in  a  morbid  manner  within  a  comparatively  limited 
circle,  and  only  engages  certain  zones  of  the  cortical 
substance,  the  others  remaining  comparatively  un- 
affected ;    as   we    see   for   instance,   certain   cutaneous 

*  See  Billod,"  Annales  Medico-psychol.,"  1861,  p.  541.    Lesions  of  Associa- 
tion of  ideas  ;  fixed  ideas. 


PERTURBATIONS   OF  AUTOMATIC  ACTIVITY.      20/ 

phenomena  reveal  themselves  in  patches,  in  little 
islets  on  the  surface  of  the  skin,  leaving  sound  regions 
at  intervals.  Thus,  in  the  cases  to  which  we  allude, 
the  perceptive  regions  of  the  sciisoriinn — those  in  which 
the  manifestations  of  conscious  personality  take  place, 
are  sometimes  spared,  and  in  a  condition  of  complete 
integrity,  while  the  neighbouring  regions  are  invaded  by 
different  kinds  of  morbid  processes  ;  and  then  we 
witness  a  strange  phenomenon — a  sort  of  duplication 
of  the  mental  unity.  The  individual,  thus  divided  into 
two  parts — one  portion  of  himself  remaining  healthy, 
while  the  other  is  at  the  mercy  of  the  phenomena  of 
automatic,  involuntary  impulse — looks  on,  as  a  conscious 
spectator^  at  certain  extravagant  acts  that  he  is  forced  to 
commit,  at  certain  senseless  words  that  he  utters.  He 
is  in  a  manner  reduced  to  the  painful  position  of  the 
tetanic  patient,  who  at  the  moment  of  the  attack  sees 
his  muscles  escape  from  the  influence  of  his  will,  con- 
tract under  the  influence  of  the  cells  of  the  spinal  cord, 
in  a  paroxysm  of  automatic,  irresistible  activity,  and 
thus  become  unwieldable  instruments  which  cease  to 
belong  to  him. 

The  annals  of  .mental  diseases  include  numerous  ex- 
amples of  this  state  of  dissociation  of  the  vital  forces  of 
cerebral  activity.  There  are  patients  sometimes  who 
write  and  describe  their  distresses — the  involuntary 
agonies  through  which  they  pass,  the  words  they  have 
pronounced  unwittingly ;  how  they  are  impelled  to 
speak  in  spite  of  themselves,  to  say  what  they  ^\  ould 
not  have  wished  to  say,  to  go  through  ridiculous  gesti- 
culations, and  to  commit  extravagances  they  believe 
themselves  incapable  of  restraining. 


208  THE  BRAIN   AND   ITS   FUNCTIONS. 

A  lady  described  by  Falret  uttered  cries,  committecl 
all  sorts  of  disorderly  acts,  and  felt  herself  the  more 
to  be  pitied,  because  she  knew  that  they  were  acts  of 
madness,  but  could  not  avoid  committing  them.*  A 
patient  described  by  Moreau  (of  Tours)  presented 
analogous  symptoms  : — 

X ,    in    consequence    of   grief,    became   irritable 

in  temper,  and  was  seized  with  eccentric  ideas  which 
his  reason  disapproved.  Suddenly  the  idea  of  tossing 
his  bed  would  occur  to  him  ;  but  he  would  ask  himself 
what  was  the  good  of  it.  Or  he  would  be  tempted  to 
throw  his  hat  upon  the  ground  without  a  motive.  In 
conversation  if  any  one  dared  to  contradict  him,  a  sud- 
den desire  to  beat  his  adversaiy  seized  him,  but  he  re- 
strained himself  by  thinking  of  the  absurdity  he  would 
thus  commit ;  and  a  crowd  of  delirious  ideas  would  in- 
cessantly traverse  his  mind  without  his  permitting  any 
one  to  suspect  him  of  madness,  so  short  was  the  duration 
of  his  paroxysm.-f 

These  strange  phenomena,  these  general  or  partial 
deliriums,  these  strange  impulses,  of  which  w^e  see  abor- 
tive specimens  in  certain  pregnant  women,  constitute,  in 
the  form  of  suicidal  or  homicidal  impulses,  the  essen- 
tial morbid  elements,  and  in  a  manner  the  primary 
factors  of  mental  pathology.  They  are  all,  in  different 
degrees,  derived  from  the  fundamental  properties  of  the 
cerebral  cell,  from  its  automatic  activity  past  into  a 
phase  of  inveterate  erethism.  It  is  always  the  same 
fundamental  property  which  is  at  the  bottom  of  all  morbid 

*  Falret,  "  Annales  Medico-psycholog.,"  1870,  p.  117.    Conscious  Lunatics. 
\  Unusual    impulses,   with    disorder   of    intelligence.     "Annales   Medico- 
psyehol.,"  p.  84,  1857. 


PERTURBATIONS  OF  AUTOMATIC  ACTIVITY.      209 

manifestations  of  the  brain,  and  which,  always  present, 
always  identical  with  itself,  either  in  normal  or  mcrbd 
conditions  of  the  life  of  the  brain,  beconies  the  source 
of  all  the  disorders  and  all  the  anomalies  of  mental 
life. 


PART  III. 


EVOLUTION  OF  THE  PROCESSES  OF  CEREBRAL 

ACTIVITY. 


Having  thus  far  considered  the  elements  of  cerebral 
activity  as  individual  simple  forces  in  the  statical  con- 
dition, we  shall,  in  this  third  part  of  the  work,  consider 
them  from  a  dynamic  point  of  view,  as  living  forces 
in  movement,  in  combination  one  with  another,  effect- 
ing reciprocal  reactions,  and  co-operating  in  the  different 
modes  of  mental  activity. 

One  general  fact  governs  the  essential  organization  of 
the  cerebral  cortex  (see  p.  15).  This  fact  is  the  admir- 
able order,  the  regular  subordination  which  is  established 
in  the  grouping  and  methodical  distribution  of  all  the 
elements  of  this  cortical  substance.  In  all  its  regions  the 
zones  of  cells  are  arranged  one  below  another  in  thicker 
or  thinner  strata  ;  they  are  strictly  united  one  with 
another,  both  transversely  and  horizontally  as  regards 
this  substance  ;  the  regions  of  small  cells,  moreover, 
everywhere  occupy  the  superficial  sub-meningeal  zones, 
while  the  regions  of  large  cells  are  localized  in  the  deep 
res^ions,  and  communicate  with  the  preceding  by  a  series 
of   intermediate  links — strata  of  cells  which  serve    as 


212  THE  BRAIN   AND   ITS   FUNCTIONS. 

a  transition  between  these  two  isolated  regions.  If  we 
compare  this  simple  disposition,  which  is  the  anatomic 
formula  in  which  the  economy  of  the  constitution  of 
the  cerebral  cortex  is  epitomized,  with  that  which  regu- 
lates the  reciprocal  relations  of  the  nerve-cells  of  the 
spinal  cord,  we  immediately  perceive  that  it  presents 
certain  analogical  characters  which  in  a  manner  explain 
themselves  ;  and  we  cannot  avoid  recognizing  the  fact 
that  if  in  both  instances  there  are  analogies  from  an 
anatomic  point  of  view,  that  is  to  say  regions  of  large 
cells  indirectly  anastomosing  one  with  another,  there 
should  similarly  be  physiological  analogies  as  regards 
the  mechanism  of  the  activity  of  these  similar  ele- 
ments. 

Now,  as  experience  proves  that  the  nervous  currents 
pass  across  the  spinal  cord  from  the  smaller  to  the  larger 
cells,  and  that  these  latter  never  enter  into  activity  spon- 
taneously, but  merely  in  consequence  of  an  incidental 
excito-motor  excitation,  which  they  simply  reflect,  we 
cannot  help  admitting,  from  the  most  legitimate  analogy, 
that  the  nervous  actions  must  be  evolved  in  a  similar 
manner  throughout  the  stratified  elements  of  the  zones 
of  the  cerebral  cortex.  We  may  therefore  conclude 
that  the  regions  of  small  cells  in  the  cortex  represent  in 
the  brain  the  posterior  grey  regions  of  the  spinal  cord, 
and  that,  like  them,  they  are  the  territory  of  dissemi- 
nation of  sensitive  impressions,  designed  to  retain  them, 
store  them  up,  and  afterwards  propagate  them  to  the 
subjacent  zones. 

From  the  clear  analogies  which  exist  between  these 
two  spheres  of  nervous  activity,  the  spinal  cord  and 
the  brain,  we  are  therefore   led  to  the  conclusion  tiiat 


PROCESSES   OF  CEREBRAL  ACTIVITY.  213 

the  different  zones  of  the  cortical  substance,  taken  as  a 
whole,  represent,  as  it  were,  a  series  of  sensori-motor 
organs  conceived  on  the  same  plan  as  that  of  the 
similar  organs  of  the  spinal  axis ;  that  the  nervous 
activities  are  developed  throughout  its  tissue  as 
throughout  that  of  the  spinal  grey  matter ;  and  that  in 
both  instances  the  processes  which  take  place  are  always 
• — except  for  differences  of  medium,  the  different  qualities 
of  the  elements  called  into  play,  the  amplitude  and 
complexity  of  the  different  phases  of  which  they  are 
composed — similar  processes,  reducible  to  the  same 
primordial  phenomena.  It  is  always  a  phenomenon 
of  sensibility  that  produces  the  movement,  and  excites 
the  activity  of  the  motor  cell  ;  and  the  motor  act  itself, 
whether  we  have  to  do  with  the  spinal  cord  or  the 
brain,  is  always,  as  regards  its  dynamic  signification, 
merely  a  secondary"  and  subordinate  phenomenon,  the 
return  effect  of  a  sensitive  impression  transformed. 

This  being  the  case,  the  phenomena  of  cerebral 
acti\-ity,  as  regards  their  successive  development,  may 
be  briefly  reduced  to  a  series  of  processes — of  regularly- 
linked  physiological  operations,  all  derived  one  from 
another,  becoming  complicated  in  their  diverse  phases, 
but  always  having  a  common  basis  of  elementary  opera- 
tions. 

It  is  always  a  phenomenon  of  sensibility,  an  anterior 
sensorial  impression,  present  or  past,  that  marks  the 
point  of  departure,  and  becomes,  in  a  more  or  less 
sensible  form,  the  primary  stimulation  that  induces 
the  movement.  In  a  word,  it  is  always  an  agitation 
of  the  sensoriuin,  an  emotion  of  the  personality,  that 
expresses,  through  the  infinite  series  of  cerebral  opera- 


214  THE  BRAIN  AND  ITS   FUNCTIONS. 

tions,   the   condition    of   erethism   which    it    has    ex- 
perienced. 

Hence  there  are  three  natural  phases  under  which  we 
shall  successively  consider  the  mode  of  evolution  of  the 
different  processes  of  cerebral  activity. 

1.  A  phase  of  incidence,  which  corresponds  to  the 
moment  when  the  external  impressions  arrive  in  the 
plexuses  of  the  sensor iitrn  and  are  perceived  there 
(phenomenon  of  attention — genesis  of  the  notion  of 
personality — conscious  perception). 

2.  An  intermediate  phase,  during  which  the  affected 
elements  of  the  cortical  substance  enter  into  active 
participation  with  the  external  impression,  transformed 
into  a  psycho-intellectual  excitation.  (Dissemination 
of  sensorial  impressions  in  the  psycho-intellectual  sphere 
— evolution  and  transformation  of  these  impressions — 
operations  of  the  judgment,  etc.) 

3.  A  phase  of  reflexion,  which  corresponds  to  the 
moment  in  which  the  primordial  excitation,  being 
propagated  through  the  plexuses  of  the  cortex,  passes 
outwards,  and  expresses,  by  voluntary  motor  reactions, 
the  different  states  of  the  previously  impressed  senso- 
rmm.  (Genesis  and  evolution  of  the  phenomena  of 
voluntary  motion.) 


BOOK    I. 

PHASE   OF   INCIDENCE   OF   THE   PROCESSES   OF 
CEREBRAL  ACTIVITY. 


CHAPTER    I. 

ATTENTION. 

The  period  of  incidence  of  the  process  of  cerebral 
activity  occurs  at  the  moment  when  the  sensorial  ex- 
citations darted  from  the  different  centres  of  the  optic 
thalami  are  distributed  to  the  different  regions  of  the 
seiisorium^  upon  which  they  thus  produce  a  consecutive 
impression  (Fig.  6,  p.  6i).  We  have  already  several 
times  insisted  upon  the  different  phases  of  evolution  of 
the  phenomena  of  sensibility,  and  shown  that  this 
simple  physical  impression  produced  by  the  external 
world  is  transformed,  as  it  becomes  incorporated  with 
the  organic  tissues,  into  nervous  vibrations,  and  that 
these  nervous  vibrations,  passing  through  successive 
agglomerations  of  cells,  undergo  the  action  of  the  dif- 
ferent media  through  which  they  pass,  until  they  arrive 
transformed  and  purified  in  the  plexuses  of  the  cortical 
substance,  which  are  set  in  motion,  impressed,  and  vivi- 
fied by  them  alone. 


2l6  THE  BRAIN    AND  iTS   FUNCTIONS. 

The  regions  of  the  sensorium,  which  are  the  living 
sources  that  feed  all  the  activities  of  animal  life  as  at 
a  common  reservoir,  are  then,  before  they  react  by 
radiating  outwards  the  forces  that  they  create  on  the 
spot,  themselves  the  tributaries  of  excitations  from  the 
external  world,  which,  like  an  electric  spark  dispersed 
throughout  their  tissues,  suddenly  excite  and  develop 
their  latent  energies.  It  is  necessary,  therefore,  as  a 
fundamental  condition  of  the  evolution  of  the  intra- 
cerebral processes,  that  sensorial  impressions  shall  be 
regularly  conducted  during  their  period  of  incidence, 
that  they  shall  be  distributed  according  to  the  physio- 
logical laws  we  have  described,  and  that,  besides,  they 
shall  be  received y  propagated^  and  retained.  At  this 
precise  moment  of  cerebral  activity,  a  delicate,  precise, 
and  rapid  phenomenon  takes  place.  This  is  called  the 
phenomenon  of  attention.  It  is  quite  comparable  to 
that  which  we  have  already  described  at  the  other 
pole  of  the  nervous  system,  at  the  moment  when 
sensitive  impressions  come  into  contact  with  the  peri- 
pheral plexuses,  and  when  the  external  excitation, 
becoming  incorporated  with  the  nervous  tissue,  loses 
in  an  instant  the  qualities  of  a  purely  physical,  to  assume 
those  of  a  purely  nervous  excitation. 

At  the  periphery,  at  the  precise  moment  when  the 
external  excitation,  represented  either  by  a  luminous  or 
a  sonorous  vibration,  or  by  a  material  impression, 
impinges  upon  the  sensorial  plexuses,  an  inward 
phenomenon  of  impregnation  or  transformation  of  force 
occurs.  The  natural  sensibility  of  the  nervous  element 
is  affected  :  it  becomes  erect,  is  arrested,  is  attentive ;  and 
from  this  intimate  contact  with  the  external  vibration 


ATTENTION.  2\^ 

it  enters  into  a  new  state  ;  a  specific  impression  is 
made  upon  it,  which  passes  from  the  external  world  from 
which  it  is  derived,  to  explode  in  the  sensorium  itself. 

The  plexuses  of  the  sensorium,  which  themselves 
represent  a  vast  sensitive  surface  open  to  external  exci- 
tations, are  the  theatre  of  phenomena  of  the  same 
kind.  For  there  each  excitation  from  the  external  world 
arrives  in  a  quintessential  form,  intellectualized  by  the 
metabolic  action  of  the  centres  of  the  optic  thalamus. 
Henceforth  it  represents  only  the  distant  and  trans- 
formed echo  of  an  impression,  which  was  purely 
physical  when  it  made  its  first  appearance  in  the 
organism.  Here  also,  in  order  that  this  incident  im- 
pression shall  penetrate  into  the  plexuses  of  the 
sensoriiLin  and  become  incorporated  with  them,  it  is 
necessary  that  it  shall  find  in  them  proper  conditions 
of  receptivity,  that  their  natural  sensibility  shall  be  ex- 
cited, that  it  shall  be  seized  upon,  and  that  a  species  of 
similar  erethism  shall  be  developed.  This  is  what,  in 
fact,  takes  place  at  the  moment  when  the  exci- 
tation arrives  in  the  seiisormm.  Its  impregnation 
does  not  take  place  coldly,  nor  without  a  local  reaction 
and  an  active  participation  of  the  nervous  element 
thrown  into  agitation.  There  is  a  period  of  physiologi- 
cal erethism  which  this  element  then  manifests  at  a  given 
and  variable  point  in  the  cerebral  cortex.  It  is,  in  fact, 
actually  recognized  that,  at  the  moment  when  this  subtle 
phenomenon  takes  place,  there  is  a  local  development  of 
heat,  which  is  disengaged  in  the  cerebral  region  that 
becomes  active  (experiments  of  Schifif,  see  p.  'j'j)^  and 
that  this  reaction  expresses  the  active  participation,  the 

attentive  state  of  the  elements  of  the  sensorium  which 
i6 


2lS  THE  BRAIN   AND   ITS   FUNCTIONS. 

receive  the  excitation,  at  the  moment  when  they  are 
impregnated  by  it,  and  transform  the  purely  sensorial 
excitation  into  a  psychical  impression. 

Attention,  which  marks  the  first  phase  of  all  the  pro- 
cesses of  cerebral  activity,  is,  then,  a  phenomenon  similar 
to  all  those  developed  in  the  peripheral  plexuses  of 
the  system  when  they  are  impressed  by  excitations 
from  the  external  world.  It  is  the  sensorium  itself, 
the  sensitive  plexuses  of  our  organism,  the  conceptive 
regions  wherein  the  notion  of  our  personality  dwells, 
that  are  immediately  engaged  and  become  conscious  of 
the  inward  phenomenon  which  occurs.  It  is  from  this 
very  fact  that  the  operations  of  the  attention  are  always, 
par  excellence,  conscious  operations,  which  imply  the 
necessary  participation  of  the  entire  human  person- 
ality. 

Ihus,  then,  in  order  that  the  processes  of  cerebral 
activity,  by  virtue  of  which  attention  is  exercised,  shall 
be  evolved  in  a  regular  manner,  it  is  necessary  that  two 
indispensable  conditions  shall  concur :  on  the  one  hand 
the  registration  of  the  first  sensorial  impression,  regu- 
larly effected  in  the  peripheral  plexuses  at  the  moment 
of  its  genesis ;  and  on  the  other  hand  the  active, 
spontaneous,  and  original  participation  of  the  elements 
of  the  sensorium,  which  must  vibrate  in  a  concordant 
manner  and  enter  into  unison  with  the  impressions 
radiated  from  the  peripheral  regions.  It  is  necessary, 
then,  that  between  these  two  poles  of  the  system,  there 
.«ihall  be  a  simultaneous  co-operation. 

On  the  other  hand,  it  is  also  necessary  that  at  the 
moment  when  the  excitation  from  the  external  world 
arrives  in  the  sensoriiLin.  it  shall  be  introduced  methodi- 


ATTENTION.  219 

cally,  and  in  a  gradual  manner  ;  that  it  shall  work  its 
passage  independently;  and  that,  at  the  moment  at 
which  it  is  there  deposited,  it  shall  vibrate  alone, 
and  alone  imprint  the  records  of  its  presence  upon 
the  plexuses  of  the  scnsormm.  In  a  word,  it  is  neces- 
sary even  in  optical  experiments,  when  we  wish  to  study 
the  elementary  properties  of  a  luminous  ray,  that  we 
shall  carefully  eliminate  the  rays  of  diffused  light,  and 
cover  the  head  with  a  black  veil  to  eliminate  from  the 
eye  the  incident  rays — and  just  so,  for  the  perfect  ac- 
complishment of  the  phenomena  of  consciotcs  attention, 
in  order  that  these  shall  produce  their  maximum  of  effect 
it  is  necessary  that  simultaneous  and  approximate  im- 
pressions shall  not  come  to  join  the  principal  impression, 
and  eclipse  by  their  presence  its  intra-cerebral  radiation. 
To  be  attentive  it  is,  then,  necessary  simultaneously  to 
receive  impressions  from  without,  and  to  admit  them 
only  in  a  gradual  and  successive  manner.  Without  these 
fundamental  conditions  the  process  is  abortive,  and  con- 
fusion of  impressions  and  want  of  precision  in  the 
notions  acquired,  are  the  sole  and  ultimate  result  of  this 
abortive  operation. 

It  is  necessary,  then,  that  one  single  impression  at  a 
time  shall  be  imprinted  upon  the  sensoriiim,  and  that, 
moreover,  the  elements  of  the  sensoriiim  shall  them- 
selves be  in  a  kind  of  silence  and  relative  calm. 

In  fact,  where  lively  preoccupations,  or  a  prolonged 
intellectual  effort  maintain  in  certain  zones  of  the  cere- 
bral substance  a  period  of  erethism  more  or  less  per- 
sistent, the  result  is  that  this  local  over-activity,  simply 
from  its  being  in  possession  of  the  field  where  it  has 
originated,  will  stifle  by  its  intensity  impressions  from 


220  THE   BRAIN   AND   ITS   FUNCTIONS. 

the  external  world.  Subjectivity  predominates,  and 
itself  alone  absorbs  the  cerebral  activity ;  so  that  exter- 
nal impressions  grow  dull  on  arriving,  only  penetrating 
into  the  regions  of  conscious  personality,  when  fore- 
stalled by  excitations  originating  on  the  spot.  They 
are  consequently  as  though  they  had  never  arrived.- 
It  is  necessary,  therefore,  that  at  the  moment  when 
the  external  impression  arrives  in  the  brain,  it  shall 
find  the  sensitive  regions  available,  in  a  healthy  con- 
dition, and  free  from  every  local  cause  of  internal 
excitation. 

In  order  that  the  process  shall  be  completely  effected, 
another  special  condition  is  finally  necessary — a  condi- 
tion of  receptivity  similar  to  that  which,  as  we  have 
seen,  must  exist  in  the  peripheral  regions  of  the  system. 
It  is  necessary  that  the  impressed  cerebral  cell  shall, 
like  the  cell  of  the  sensorial  plexuses,  be  endowed  with 
a  certain  special  retentive  power,  and  with  a  certain  energy 
for  supporting  fatigue  ;  for  it  is  at  the  expense  of  its 
substance  that  it  produces  movement,  vibrates,  enters 
into  erethism,  and  becomes  attentive.* 

We  all  know  that  it  is  impossible  to  prolong  efforts 
of  attention  beyond  certain  limits, — that  we  cannot, 
for  instance,  fix  our  attention  in  an  undetermined 
manner  for  a  prolonged  period  upon  some  petty  fact, 
which  only  involves  a  single  sensorial  impression.  It 
is  only  by  mnemonic  artifices  that  we  succeed  in 
reviving  the  fleeting  impression  by  a  series  of  suc- 
cessive   instigations    producing    continuance    of     the 

*  The  phenomena  of  fatigue,  or  functional  exhaustion  in  the  nervous 
elements,  reveal  themselves  very  clearly,  as  we  have  already  explained  in 
si-'eakin'T  of  the  retina,  which  is  rapidly  fatigued  by  certain  luminous  raya 
which  have  too  continuouslv  affected  it. 


ATTENTION.  221 

act  of  attention  *  This  distraction  takes  place  by 
reason  of  the  vital  forces  of  cerebral  activity  them- 
selves ;  for  as  certain  regions  of  the  brain,  fatigued  by 
sustained  attention  become  inactive,  other  cell  terri- 
tories, reposed  and  fresh,  automatically  come  into  action, 
by  virtue  of  their  native  energies,  and  monopolize 
the  vital  forces  of  these  regions  of  the  conscious  per- 
sonality for  their  own  profit.  Thus,  we  may  say  that  the 
failure  of  attention,  and  easy  distraction,  imply  the  rapid 
fatigue  or  need  of  repose  of  the  cerebral  cells  ;  so  that 
we  are  led  to  the  conclusion  that  the  vigour  of  attention 
is,  to  some  extent,  a  measure  of  the  degree  of  vigour  of 
the  mental  faculties  ;  that  it  is  the  external  expression  of 
the  energy  and  vitality  of  the  cerebral  elements  ;  as, 
in  the  appreciation  of  motor  phenomena,  the  continuity 
of  effort  is  proportional  to  the  disposable  motor  force.f 
Functional  Perturbations. — The  processes  of  attention 
represent,  then,  as  we  have  just  explained,  a  synthesis 
of  the  active  operations  of  the  brain,  in  which  the  phe- 
nomena which  occur  in  the  periphery  of  the  nervous 
system  in  the  sensorial  regions  on  the  one  hand,  and  the 
phenomena  which  are  developed  in  the  central  regions 
of  the  sensorium  where  they  come  directly  in  contact 
with  external  excitation,  on  the  other  hand,  are  fused 
together.  We  can  therefore  comprehend  how,  when 
these  two  fundamental  conditions  happen  to  be  disturbed 

*  To  make  use  of  an  analogous  illustration,  we  know,  that  the  continuity  of 
muscular  contraction  is  merely  the  result  of  a  series  of  successive  shocks. 

f  Hemiplegic  patients,  whose  brains  are  partially  disorganized,  are  very 
rapidly  fatigued  as  regards  the  amount  of  attention  they  lend  those  who  speaic 
to  them.  Patients  with  dementia,  whose  cortical  substance  is  more  or  less  pro- 
foundly degenerated,  are  in  the  same  condition  :  they  only  lend  a  very  limited 
degree  of  attention  to  words  addressed  to  them,  and  cannot  sustain  a  con- 
nected conversation  for  more  than  a  very  few  minutes. 


222  THE  BRAIN   AND   ITS   FUNCTIONS. 

in  their  constituent  elements,  whether  in  the  peripheral 
or  central  regions,  the  processes  of  attention  are,  at  the 
same  time,  disturbed  and  arrested  in  their  regular  evolu- 
tion. 

Thus,  when  it  is  the  peripheral  regions  that  cease  to 
be  in  their  normal  conditions  of  receptivity,  when  the 
sensorial  apparatuses  are  not  adjusted  in  the  required 
direction — when,  for  instance,  certain  sensorial  plexuses 
are  struck  with  anaesthesia — the  unperceived  and  un- 
reeistered  excitations  from  the  external  world  are 
practically  absent  as  far  as  the  sensorium  is  concerned. 

Thus,  physicians  are  well  aware  how  indifferent  all 
anaesthetic  individuals  are  to  oscillations  of  tempera- 
ture in  the  atmosphere  in  contact  with  their  bodies  ; 
how  little  attention  they  give  to  what  directly  touches 
them,  yet  only  produces  in  them  a  confused  impression  ; 
how  certain  individuals  with  well-marked  myopia  have 
a  vague  and  blinking  mode  of  looking  at  those  things 
in  the  surrounding  visual  field  which  they  do  not  see, 
and  to  which  consequently  they  pay  no  attention ;  how 
easily  the  deaf  are  distracted,  only  following  with 
much  trouble  the  series  of  ideas  brought  before  them  ; 
how  in  a  great  number  of  individuals  attacked  with 
mental  diseases  the  systematization  of  certain  forms 
of  delirium  has  no  other  cause  than  a  sympathetic 
irritation,  or  sensitive  disturbances  radiating  from  the 
peripheral  regions  which  alone  attract  their  atten- 
tion. (Phenomena  of  hypochondria.)  We  know  also, 
that  when  these  same  regions  are  excited,  and  have 
arrived  at  the  pitch  of  pain,  they  keep  the  faculties  of 
attention  in  the  sensoi^uun  in  a  permanent  condition  oi 
erethism.     Every  one,  indeed,  knows  how  vehement   a 


ATTENTION.  223 

reaction  the  painful  spot  has  upon  the  sensoriinn  when 
we  suffer  in  any  point  whatsoever  of  our  sensitive 
territory  ;  how  completely  it  absorbs  all  our  attention  ; 
and  how  profoundly  its  painful  radiation  jars  upon 
our  conscious  personality,  which  is  forced  to  pay  un- 
broken attention  to  what  is  occurring. 

In  other  circumstances  it  is  the  central  regions  that 
are  engaged,  and  therefore  place  an  obstacle  in  the 
way  of  the  regular  perfection  of  the  processes  of  atten- 
tion. 

Thus,  in  idiots  and  imbeciles,  the  state  of  imperfec- 
tion of  the  nervous  system,  either  of  the  peripheral  or 
central  regions,  renders  them  dull  in  perceiving, regularly, 
impressions  from  without.  Their  senses  are  dulled, 
their  sensibility  obtuse,  and  thus  they  are  capable  of 
but  a  slight  degree  of  attention.  They  see  badly, 
hear  badly,  feel  badly,  and  their  sensoriinn  is  in 
consequence  in  a  similar  condition  of  sensitive  poverty. 
Its  impressionability  for  the  things  of  the  external 
world  is  at  a  minimum,  its  sensibility  weak,  and  con- 
sequently it  is  difficult  to  provoke  the  condition  of 
physiological  erethism  necessary  for  the  absorption  ot 
the  external  impression. 

Thus  it  is  that  defect  of  attention  is  the  rule  in  these 
special  forms  of  mental  degradation,  and  it  is  not  with- 
out reason  that  Esquirol  has  connected  the  inaptitude 
of  idiots  for  education  with  their  defect  of  attention.* 

•  "  Imbeciles  and  idiots  are  deprived  of  the  faculty  of  attention,"  says 
Esquirol.  "I  have  repeatedly  made  this  observation  with  regard  to  them. 
Wishing  to  mould  in  plaster  a  great  number  of  insane  persons,  I  was  able  to 
do  so  even  with  furious  maniacs  and  melancholies;  but  I  never  could  suc- 
Ct^ed  in  getting  imbeciles  to  ke<  p  Uieir  eyes  closed  long  enough  to  apply  the 
plaster,  however  good  the  initniion  with  which  tl)ey  went  to  work.     I  haveeven 


224  THE   BRAIN   AND   ITS  FUNCTIONS. 

In  all  forms  of  mental  disease  the  faculty  of  atten- 
tion becomes  gradually  weaker,  and  presents,  according 
to  the  intensity  of  the  morbid  process,  different  and 
fatally  progressive  modifications. 

In  a  general  way,  in  persons  with  hallucinations,  in- 
dividuals attacked  with  acute  or  chronic  mania,  etc.  etc., 
the  forces  of  attention  cease  to  take  effect,  the  pheno- 
mena of  the  external  world  no  longer  produce  in  the 
sensoriimi  anything  more  than  an  abortive  impression. 
Morbid  excitations  are  developed  locally  in  the  very 
regions  of  subjectivity,  which  become  erethised  of  their 
own  accord,  and  thus  virtually  become  an  insurmount- 
able barrier  between  the  individual  and  the  surrounding 
medium.  The  patient,  thus  shut  up  from  external  sounds, 
a  stranger  to  everything  that  passes  around  him,  lends 
but  an  inattentive  ear  to  the  things  of  the  external  world. 
He  lives,  as  people  say,  in  himself,  upon  remembrances 
of  the  past,  and  upon  his  habitual  delirious  conceptions. 
Days  pass  away,  the  world  goes  by,  events  succeed 
around  him,  he  no  longer  pays  any  attention,  and  the 
progressive  indifference  and  invading  apathy  which 
manifest  themselves  in  him,  attest  the  gradual  exhaustion 
of  the  vital  forces  of  his  mental  activity.* 

seen  them  cry  because  the  mould  of  their  heads  has  not  succeeded,  and  several 
times  vainly  make  the  attempt  to  keep  the  pose  that  was  given  them,  not  beinu 
able  to  keep  their  eyes  shut  more  than  a  minute  or  two."  (Ksquirol,  Tome  1. 
p.  II.) 

*  There  are  circumstances  in  which,  in  the  case  of  insane  patients  whose 
intellectual  faculties  are  not  as  yet  quite  extinguished,  we  see  certain  sharp  and 
unexpected  external  excitations  come  in  to  produce  a  happy  modification  of 
their  mental  condition  and  provoke  in  them  some  manifestations  of  attention. 
Thus  Vigna  has  reported  the  history  of  certain  individuals,  who  though 
apparently  incapable  of  the  simplest  reasoning,  when  brought  into  the  presence  of 
a  person  who  overawed  tliem,  a  magistrate  for  instance,  were  much  excited  by 
ine  mfluence  of  the  new  circumsiances  in  which  they  were  placed,  and  then 


ATTENTION  225 

produced  the  elements  of  a  regular  defence,  and  thus  succeeded  in  preventing 
a  judgment  of  interdiction.     ("  Annales  M^dico-psychol."  1871,  p.  17.) 

Baillarger  has  similarly  noticed  that  in  certain  patients  with  hallucinations, 
vivid  and  sudden  impressions  may  arrest  the  morbid  working  of  their  brains 
and  induce  attention  to  what  is  going  on  around  them.  "  At  the  moment  of 
Ihe  arrival  of  the  physician,'"  he  says,  "  hallucinations  disappear.  They  cease 
to  hear  voices  ;  but  one  has  scarcely  left  them  before  they  fall  back  into  their 
Calse  conceptions."     (Annales  "Msdico-psychoL"     1845,  vol.  vi.  p.  185.) 


CHAPTER  II. 

CONSTITUTION   OF   THE   SPHERE   OF   PSYCHO- 
INTELLECTUAL  ACTIVITY. 

When  once  the  external  excitation  is  disseminated 
through  the  plexuses  of  the  cortical  substance,  and  in- 
corporated in  the  sensoruim,  developing  in  it  the  specific 
energies  of  the  cerebral  cells  that  have  received  it,  this 
new  medium  itself  comes  into  play,  and  reacts  in  the 
direct  line  of  its  latent  capacities. 

The  sphere  of  psycho-intellectual  activity  then  exhibits 
all  its  natural  riches,  all  the  stores  of  its  awakened  sensi- 
bility. It  is  suddenly  thrown  into  agitation,  reacts,  and 
thus  develops  the  marvellous  capacities  with  which  it  is 
fundamentally  endowed.  This  new  medium  which 
comes  into  play,  comprehends,  as  we  have  said,  the 
sum  of  the  purely  psychical  and  purely  intellectual 
phenomena  of  the  living  organism.  It  is  the  7'egio 
princeps  of  the  organism,  in  which  all  ends,  from  which 
all  begins,  and  which  is  the  epitome  of  the  vital  forces 
of  mental  activity. 

Now,  how  is  this  double  sphere  of  activity,  which  from 
the  dynamic  point  of  view  presents  characters  so  dis- 
tinctly marked,  and  yet  so  intimately  fused  together, 
constituted  }  How  may  it  be  ideally  conceived  as  re- 
gards the  cortical  structure  ? 


PSYCHO-INTELLECTUAL  ACTIVITY.  22/ 

These  are  questions  to  which  it  is  at  present  impossible 
to  give  a  completely  satisfactory  reply.  We  merely  know, 
from  the  anatomical  data  we  have  already  laid  before  the 
reader,  that  the  cerebral  cortex  is  made  up  of  a  series  of 
cells  superposed  in  independent  zones  and  yet  united  one 
with  another ;  and  that  these  plexuses  of  cells  directly 
receive  external  excitations,  chiefly  within  a  specially 
circumscribed  region,  thus  forming  a  vast  surface  of 
reception  for  these  excitations,  and  in  the  strict  accepta- 
tion of  the  word  a  true  sensoriuin  coninmne. 

Now  these  plexuses  of  the  sensoriuin,  constituted  by 
the  different  submeningeal  zones  of  cortical  cells,  are 
not  merely  inert  screens,  nervous  zones  destined  to 
receive  and  passively  register  the  images  of  the  external 
world.  They  are  sensitive,  living,  emotional  plexuses, 
which  become  erect  in  a  peculiar  manner  in  presence 
of  the  stimulating  excitation,  and  which,  on  its  arrival, 
like  their  fellows  in  the  peripheral  regions,  give  evi- 
dence of  the  various  manners  in  which  they  may  be 
impressed.  They  live,  they  feel,  and  what  is  more, 
they  remember  ;  for  then  it  is  that  this  new  property 
of  preserving  records  of  past  impressions,  appearing  in 
full  force,  gives  a  special  character  of  permanence  to 
all  the  excitations  that  arrive,  and  enables  them  to  sur- 
vive themselves,  to  prolong  their  existence  in  the  form 
of  memories,  and  to  be  marked  in  the  calendar  of  our 
sensitive  impressions  with  a  special  co-efficient  of  pleasure 
or  pain. 

Thus  by  these  two  fundamental  conditions,  the  arrival 
of  the  external  excitation,  and  the  appropriate  reactions 
of  the  cerebral  medium  in  which  it  is  received,  new  forces 
are  created  in  the   brain,  a  special   sphere  of  nervous 


228  THE  BRAIN   AND   ITS  FUNCTIONS. 

activity  is  developed,  in  which  the  natural  sensibility  of 
our  being,  our  conscious  personality,  represented  with 
all  its  elements  (see  p.  105)  in  the  tissue  of  the  sefi- 
sormm,  comes  to  life,  expands,  and  perfects  itself,  by  the 
coming  into  play  of  the  natural  sensibility  of  the  ele- 
ments which  compose  it.  Thus,  consequently,  former 
impressions  are  inevitably  associated  with  recent  ones ; 
the  past  life  of  diverse  emotions,  the  memory  of  days 
of  joy  or  sorrow,  is  incessantly  in  contact  with  the 
conceptive  regions  of  mental  activity ;  and  in  fine,  if 
the  sphere  of  purely  psychical  activity  be  considered 
from  a  dynamic  point  of  view,  as  the  resultant  of  all  the 
impressions  of  our  sensibility  present  and  past,  associated 
with  the  events  of  our  current  life ;  from  an  anatomical 
point  of  view,  it  may  be  conceived  of  as  localized  in  all 
that  series  of  nervous  elements  which  constitute  the 
plexuses  of  the  sensormui. 

On  the  other  hand,  if,  up  to  a  certain  point,  we 
have  some  precise  data  which  permit  us  to  suppose 
that  certain  regions  of  the  cortex  (the  regions  of  the 
small  cells)  play  the  part  of  a  common  reservoir  as 
regards  the  external  impressions  which  are  distributed 
among  them,  and  consequently  become  the  special 
territory  of  the  phenomena  of  mental  sensibility,  it 
is  as  yet  almost  entirely  impossible  to  obtain  any 
precise  data  as  to  the  real  constitution  and  topo- 
graphic situation  of  the  field  of  intellectual  activity 
proper.  It  is  only  artificially,  and  in  a  roundabout 
way,  that  we  can  succeed  in  grouping  a  it.\N  facts  with 
regard  to  the  subject. 

The  study  of  mental  diseases  shows  us,  indeed,  in  a 
precise  manner,  that  in   a  great  number  of  cases  the 


PSYCHO-INTELLECTUAL  ACTIVITY.  229 

regions  of  intellectual  activity  may  be  spared  when  the 
purely  emotional  regions,  the  regions  of  the  sensormm, 
are  profoundly  disturbed.  We  see  a  great  number  of 
insane  patients  affected  with  melancholia,  groaning  over 
their  fate,  over  the  persecutions  to  which  they  are  sub- 
jected, mourning  incessantly  about  trifles,  and  yet  capa- 
ble of  taking  note  of  what  is  going  on  around  them, 
and,  in  the  midst  of  the  disorders  of  their  agitated 
sensibility,  discerning  perfectly  what  happens  to  them, 
and  sometimes  making  very  just  reflections. 

This  dissociation  of  the  purely  emotional  and 
purely  intellectual  regions,  which  may  be  unequally 
affected,  proves,  then,  distinctly  the  complete  functional 
independence  of  the  intellectual  sphere  proper,  and  that 
of  mental  emotivity  and  sensibility. 

Now,  where  is  the  seat  of  this  sphere  of  intellectual 
activity,  which  has  its  own  special  domain,  its  peculiar 
autonomy  in  the  midst  of  the  operations  of  the  brain  ; 
and  what  are  its  connections  with  the  different  groups 
of  cells  in  the  cortex  } 

Here  again,  up  to  the  present  time,  we  have  only 
conjectures  and  probabilities  to  offer. 

In  taking  note,  however,  of  the  order  and  progress  of 
those  processes  of  cerebral  activity  which  spread  by 
propagation  from  the  superficial  submeningeal  regions 
to  the  deeper  regions  of  the  cortex,  we  cannot  help 
admitting  that  the  sphere  of  intellectual  activity  can 
only  be  set  in  motion  secondarily  and  consecutively  to 
the  impression  of  the  plexuses  of  the  sensorium.  The 
plexuses  of  the  sensoriiun  receive  the  first  onset  of  the 
external  excitations,  and  sift  them  to  some  extent 
before  propagating  them  to  the  subjacent  zones.     They 


230  THE   BRAIN   AND   ITS   FUNCTIONS. 

are  the  natural  frontiers  by  which  all  the  excltati(»ns  of 
the  external  world  must  necessarily  pass.  Now,  this 
natural  frontier  topographically  occupies  the  superficial 
regions  of  the  cortex  ;  we  may,  therefore,  provisionally 
admit  that  the  zones  of  cells  subjacent  to  the  plexuses 
of  the  sensorinm,  with  which  they  are  continuous,  are 
those  which,  without  its  being  possible  precisely  to 
limit  their  thickness,  may  be  considered  the  field  of 
action  of  the  operations  of  the  intellect  proper. 

This  theory — which  squares  with  the  facts  of  daily 
observation,  which  show  us  every  moment  how  closely 
connected  the  activity  of  the  intellect  is  with  that  of  the 
senses,  and  that  the  intellect,  in  order  to  come  into  play, 
must  first  have  received  its  stimulation  from  the  ex- 
ternal world — explains,  at  the  same  time,  how  it  is  that 
the  phenomena  of  intellectual  activity,  from  the  very 
fact  that  they  are  exercised  in  an  isolated  territory  of 
the  cortical  substance,  are  apt  to  show  themselves  in 
an  automatic  manner,  under  a  special  aspect,  as  a  com- 
pletely independent  sphere  of  activity. 

However  it  may  be,  the  intellectual  sphere,  con- 
sidered in  itself,  participates  in  the  same  dynamic  mani- 
festations we  have  observed  as  regards  its  fellow,  the 
psychical  sphere. 

Like  this,  it  becomes  active  under  the  influence  of 
the  excitations  of  the  external  world,  which  beget  in  it 
movement  and  life ;  like  it  also,  it  becomes  erect  in 
consequence,  and  develops  its  natural  energies.  But 
here  sensibility  and  emotivity  no  longer  play  the  first 
part,  as  when  the  plexuses  of  the  sensoriiLin  proper  are 
in  agitation  ;  the  purely  automatic  activities  of  the 
cells   then  develop    themselves  with    a  specific  energy 


PSYCHO-INTELLECTUAI,  ACTIVITY.  23 1 

which  is  very  significant.  If  sensibiHty  be  the  domi- 
nant note  of  the  psychical  activities,  automatism  is  the 
characteristic  of  this  special  field  of  the  life  of  the  brain. 

Everything,  in  fact,  records  itself  automatically,  and 
outside  of  the  will.  Without  our  knowledge  certain 
ideas  present  themselves,  certain  associations  are  effected 
among  themselves,  certain  reminiscences  are  evoked. 
Everything  in  this  special  domain  is  done  in  an  irre- 
sistible, inevitable,  unconscious  manner,  by  means  of 
the  automatic  activity  which  reigns  as  sovereign  and 
governs  the  series  of  the  operations  of  the  intellect.  It 
is  it,  indeed,  that  creates  new  relations,  stores  up  our 
memories,  and  daily  tacks  them  on  to  more  recent  events. 
It  is  always  present,  always  active,  and,  by  a  strange  phe- 
nomenon of  which  we  are  incessantly  the  dupes,  it  comes 
to  light  in  the  form  of  spontaneity  in  our  ideas,  our  v/ords, 
our  acts,  thus  becoming,  as  we  have  already  indicated, 
the  most  living  expression  of  the  freshness  and  vitality  of 
the  cerebral  regions  which  have  given  it  birth. 

Thus,  then,  the  sphere  of  psychical  and  that  of 
intellectual  activity  represent,  isolatedly,  each  from  the 
point  of  view  of  its  dynamic  action,  the  most  complete 
epitome  of  the  fundamental  properties  of  the  nervous 
matter.  In  the  first,  the  phenomena  of  sensibility, 
with  all  that  is  most  exquisite  and  most  perfect  in 
them,  predominate ;  in  the  second,  the  phenomena  of 
automatic  life.  These  two  regions  of  cerebral  activity, 
united  and  combined  in  a  co-ordinated  effort,  inces- 
santly lend  each  other  mutual  support.  They  dovetail 
into  one  another  in  all  the  daily  manifestations  of 
cerebral  life,  the  one  borrowinsf  from  the  other  the 
elements  which   it  needs ;  so   that  from    this  intimate 


232  THE  BRAIN  AND   ITS  FUNCTIONS. 

conseiisiiSy  this  co-operation  of  all  the  vital  forces  of  the 
nervous  elements,  laid  under  requisition  in  their  totality, 
emerges  a  new  notion,  of  which  we  have,  so  far,  but 
sketched  the  genesis — a  notion  of  a  whole,  which  is,  in  a 
manner,  the  synthesis  of  all  our  mental  activities ;  that 
is  to  say,  the  notion  of  our  own  personality.  Upon 
this  subject  we  are  now  about  to  enter. 


CHAPTER    III. 

GENESIS   OF   THE   NOTION   OF   PERSONALITY, 

The  notion  of  our  essential  personality — :that  notio 
pririceps  around  which  all  the  phenomena  of  our  mental 
activity  revolve—  arises,  as  we  have  already  hinted,  from 
the  intimate  contact  between  the  sphere  of  psychical 
activity  and  the  intellectual  sphere.  It  is  a  complex 
phenomenon,  which  undergoes  development ;  a  true 
physiological  process  which  has  its  phases  of  evolution, 
its  own  mode  of  origin,  its  manifold  conditions  on  which 
its  life  and  endurance  depend,  and  its  passing  moments 
of  disturbance  during  which  it  may  be  eclipsed  and 
momentarily  disappear. 

The  elements  of  the  vegetative  and  sensitive  sensi- 
bility of  the  living  organism*  enter  as  primary  factors 
into  the  genesis  of  the  notion  of  our  personality,  and 
the  effective  participation  of  the  elements  of  the  sen- 
soriiim  completes  and  perfects  it. 

We  have  already  shown,  indeed,  that  by  means  of 
the  nervous  system,  the  elements  of  sensibility  may 
be  directed  and  drained  away  from  the  regions  where 
they  originate,  and  transported  to  a  distance  into  the 
plexuses  of  the  sensorium^  which  are  the  common 
reservoir  of  all  the  partial  sensibilities  of  the  organism. 

*  See  p.  105,  &c. 
17 


234  THE  BRAIN   AND  ITS   FUNCTIONS. 

We  have  shown,  also,  that  all  the  sensitive  regions  of 
the  human  organism  find  in  this  sensoruun  a  symmetric 
point  vibrating  in  unison  with  them,  and  that  by  this 
means  our  individuality  in  its  totality,  sensitive  fibre  by 
sensitive  fibre,  is  transported  to  the  plexuses  of  the 
scnsorium  where  it  is  manifested. 

The  result  is,  that  these  plexuses  enclose  in  their 
minute  structure  our  living  and  feeling  personality  all 
complete,  the  sensitive  elements  which  constitute  it 
being  fused  into  an  inextricable  unity.  They  serve  as 
the  basis  of  its  manifestations,  they  unite  to  bring  it  to 
birth,  they  vivify  it  incessantly  by  their  own  energj-,  and 
thus,  by  always  maintaining  its  vitality  and  sensibility, 
they  keep  it  in  perpetual  contact  with  the  excitations 
of  the  external  world,  which  every  instant  flow  in. 

Through  this  subtle  mechanism,  the  notion  of  our 
personality  comes  to  life  in  us,  being  necessarily  derived 
from  a  series  of  regular  phenomena  of  the  life  of  the 
nervous  system.  All  the  diffuse  sensibilities  of  the 
organism,  each  in  its  own  key,  are,  as  we  see,  united  in 
the  plexuses  of  the  sensorium^  and  thus  become  the 
primary  materials  for  its  formation. 

As  a  natural  consequence  of  this  physiological  evolu- 
tion, from  the  very  fact  that  the  perceptive  regions  of 
the  sensoriwn  have  given  it  birth,  it  results  that  it  comes 
into  direct  contact  with  external  impressions,  and  is 
inevitably  associated  with  all  the  nervous  excitations 
these  develop  in  their  train.  It  is  constantly  informed 
of  these,  is  constantly  conscioiLS  of  all  that  passes,  of 
the  different  characters  and  degrees  of  intensity  of 
these  excitations.  It  is  impressed,  it  is  moved,  it  is 
sorry  or  glad  according  to  the  various  modes  in  which 


GENESIS   OF   THE   NOTION   OF   PERSONALITY.     235 

the  elements  of  the  seiisoriinn,  which  are  its  natural 
basis,  are  themselves  impressed  by  the  incident  stimula- 
tions. 

Thus  the  phenomena  of  conscious  perception^  looked 
at  from  the  physiological  point  of  view,  come  within 
the  natural  limits  of  regularly  accomplished  nervous 
functions.  There  is  a  vital  operation,  a  normal  process, 
which  originates  and  is  developed  by  the  mere  fact  of  the 
co-operation  of  all  the  vital  forces  of  the  nervous  system 
laid  simultaneously  under  contribution.  Like  all  the 
grand  functions  of  the  economy,  the  process  on  which 
the  notion  of  the  conscious  personality  depends,  only 
lives  and  is  maintained  by  the  incessant  concurrence  of 
all  the  nerv^ous  apparatuses  which  take  part  in  it ;  and 
this  notion  only  becomes  paramount  and  stable  in  itself 
by  the  continual  operation  of  the  organic  mechanism  by 
nr.eans  of  which  it  is  developed. 

If  an  interruption  in  the  arrival  of  external  sensi- 
tive impressions  in  the  sensoriuin  occur,  special  disturb- 
ances will  appear,  and  will  reveal  themselves  in  a  very 
characteristic  manner.  Thus  we  meet  with  certain 
patients  who,  when  affected  with  anaesthesia  of  the  lower 
limbs  (certain  forms  of  locomotor  ataxia),  say  that  when 
they  are  lying  in  bed  they  can  no  longer  feel  their 
limbs  ;  they  do  not  know  where  their  legs  are.  They 
are  no  longer  conscious  of  that  portion  of  their  person- 
ality which  is  constituted  by  their  inferior  extremities. 

When  the  currents  of  blood  which  carry  life  to  the 
cells  of  the  sciisoriiun  are  suspended,  another  order 
of  very  significant  phenomena  is  developed.  There 
is  a  sudden  arrest  of  the  working  of  the  living 
machine.     Everything  stops  at  once  ;  everything  imme- 


236  THE  BRAIN   AND   ITS   FUNCTIONS. 

diately  remains  suspended.  The  perceptive  regions  of 
the  scnsoriinn,  struck,  in  a  manner,  with  asphyxia,  are 
all  at  once  deprived  of  the  property  of  feeling  excita- 
tions from  the  surrounding  medium  ;  they  remain 
torpid,  inert,  and  the  human  personality^  ceases  at  the 
same  time  to  be  conscious  of  the  things  of  the  external 
world,  of  which  it  thus  loses  the  knowledge  (syncope, 
fainting,  epileptic  vertigo). 

Again,  if  the  plexuses  of  cells  in  the  cortical  sub- 
stance, which  are  to  a  certain  extent  isolated  as 
regards  the  arrival  of  blood  in  their  tissue,  as  they 
are  as  regards  dynamic  activity,  receive  at  a  given 
moment  more  blood  than  is  their  wont,  and  thus  assume 
a  condition  of  morbid  erethism,  the  regions  of. con- 
scious personality  remaining  comparatively  unaffected,  a 
strange  phenomenon  will  result,  in  which  the  individual, 
without  having  lost  consciousness  of  external  things, 
will  be  almost  passively  hurried  away  by  the  auto- 
matic activity  of  certain  regions  of  his  brain,  which 
will  urge  him  to  utter  words  and  to  commit  extravagant 
actions,  and  this  in  an  irresistible  manner,  and  quite 
without  the  agency  of  his  will. 

These  facts  lead  us  to  the  opinion  that  the  pheno- 
mena of  conscious  perception,  like  true  physiological 
processes,  are  decomposable  by  analysis  into  successive 
phases,  and  that  they  only  develop  and  come  to  per- 
fection through  the  integrity  of  the  different  media 
which  give  them  birth. 

From  this  point  of  view  they  are  quite  comparable 
to  the  phenomena  of  haematosis,  which  take  place 
in  an  incessant  and  continuous  manner  only  by 
means    of   the    effective    co-operation   of    a   series   of 


GENESIS  OF  THE  NOTION   OF   PERSONALITY.     237 

apparatuses  of  organic  life,  for  this  common  end. 
Ila^matosis  is,  in  its  essence,  a  fundamental  operation  as 
important  in  the  sphere  of  the  phenomena  of  organic 
life  as  conscious  perception  in  that  of  the  phenomena  of 
psychical  activity.  In  the  first  case  it  is  the  arrival  of 
the  oxygen  that  comes  to  animate  the  blood-corpuscle 
and  render  the  venous  blood  ruddy  at  the  moment  of 
its  passage  into  the  pulmonary  tissue.  In  the  second 
case  it  is  the  incessant  and  uninterrupted  arrival  of 
stimulations  from  the  external  world  which  animates 
the  cerebral  cell  and  excites  its  latent  energies.  In 
both  cases  it  is  the  non-interruption  of  the  arrival  of 
the  external  element  which  is  the  cause  of  the  perpetual 
maintenance  of  the  function  which  occurs  as  its  con- 
sequence ;  so  much  so  that  the  notion  of  conscious 
personality  is,  in  its  essence,  a  phenomenon  of  vital 
order  which  exists  only  through  the  continuity  and  co- 
operation of  the  nervous  apparatuses  laid  ujider  contri- 
butioxi. 


CHAPTER  IV. 

DEVELOrMENT  OF  THE  NOTION  OF  PERSONALITY. 

Like  all  the  operations  of  the  organism  in  action,  the 
notion  of  our  conscious  personality  does  not  all  at 
once  arrive  at  the  degree  of  complete  perfection  which 
it  presents  in  the  adult.  It  passes  through  successive 
phases  of  development ;  it  is  at  first  rudimentary  in  the 
individual  just  born,  and  it  follows  by  degrees,  in  its 
natural  development,  the  successive  progress  of  the 
evolution  of  the  nervous  apparatuses  which  are  its 
basis. 

During  the  first  period  of  the  life  of  the  infant 
it  is  vague,  indefinite,  and  as  confused  as  the  organic 
machinery  which  produces  it.  The  plexuses  of  the  sen- 
soriiim  are  scarcely  formed,  cerebral  biologic  development 
waits  upon  that  of  the  spinal  axis,  so  that  the  automatic 
life  then  reigns  alone. 

It  is  only  little  by  little,  by  means  of  the  development 
of  the  sensorial  apparatuses  and  those  of  the  cerebral 
activity,  that  the  infant  comes  to  distinguish  his 
sensations,  to  see,  to  hear,  and  to  keep  a  conscious 
memory  of  impressions  perceived.  At  the  same  time 
he  sees  himself,  feels  himself  walk  and  move,  has  the 
conscious  notion  of  his  own  activity  ;  and  what  is  more, 
he  feels  what  things  have  pleased  or  displeased  the  sen- 


DEVELOP^IENT  OF  THE  NOTION  OF  PERSONALITY.   239 

sitlve   regions  of  his  organism,  and  have    in  any  way- 
provoked  the  intervention  of  his  personaHty. 

On  the  other  hand  he  touches  and  sees  surrounding 
objects;  he  feels  that  all  that  surrounds  him  is  not  him- 
self, that  it  is  all  external  to  him  and  his  individual  sensi- 
bility. Henceforth  an  incessant  labour  begins  insen- 
sibly in  his  mind  ;  a  natural  selection  takes  place  in  the 
mass  of  the  acquisitions  he  has  made,  and  while  all  the 
impressions  radiating  from  the  sensitive  regions  of  his 
organism  are  fused  into  a  homogeneous  notion  in  his 
sensoruun — the  essential  notion  of  what  is  himself,  of 
his  own  personality — impressions  from  the  external 
world,  also  perceived  in  the  sensoritim,  are  and  remain 
isolated,  forming  a  heterogeneous  store,  entirely  apart, 
and  henceforth  classed  as  a  contingent  of  external 
origin,  independent  of  the  former. 

At  this  moment  the  young  child,  whose  seizsoriiini  has, 
by  its  mere  vital  force,  accomplished  this  first  selection 
from  the  natural  excitations  which  have  impressed  him, 
is  (to  make  use  of  a  comparison  we  have  previously 
employed)  in  the  situation  of  a  person  placed  in  a  dark 
chamber,  who  sees  his  own  image  represented  on  a 
screen  with  that  of  external  objects,  and  who  cannot 
at  first  recognize  his  features  nor  abstract  them  from 
the  objects  he  sees  imaged  on  the  screen.  Henceforth 
in  the  mind  of  the  young  child  in  process  of  develop- 
ment, the  phenomena  of  subjectivity  and  objectivity 
have  an  isolated  existence. 

This,  however,  is  but  the  first  step.  Other  opera- 
tions of  as  great  importance  will  soon  begin — his 
sensibility  will  reveal  itself  externally,  he  will  begin 
to  speak. 


240  THE   BRAIN   AND   ITS   FUNCTIONS. 

This  work  of  natural  selection  between  internal  and 
external  impressions  takes  place  unconsciously  and  in 
silence  in  the  brain  of  the  young  child ;  his  cerebral 
activity  is  not  yet  brought  into  play  with  all  its  riches  ; 
he  outwardly  expresses  but  few  of  the  things  which 
take  place  within  him.  It  is  only  by  degrees  that  he 
advances  in  the  direction  of  mental  progress.  His  ear 
at  first  teaches  him  to  repeat  the  sounds  that  strike 
upon  it,  and  this  at  first  automatically,  like  an  echo ; 
then  his  mind  takes  its  part,  and  his  faithful  memory 
teaches  him  that  sounds  modulated  in  a  special  manner 
express  such  and  such  an  external  object,  and  that 
accordingly  the  different  emotional  conditions  of  his 
sensoriumy  his  joys  and  sorrows,  may  be  outwardly 
expressed  by  significant  vocal  consonances.  Thus, 
step  by  step,  and  efibrt  by  effort,  he  attains  to  the 
formation  of  a  series  of  abstractions,  and  to  the  com- 
prehension that  if  articulate  sounds  may  be  the  repre- 
sentative signs  of  surrounding  objects,  his  whole  per- 
sonality— his  sensitive  and  impressionable  ego — may  be 
represented  by  a  similar  abstraction  in  a  single  word, 
by  a  specific  sound  which  epitomises  it,  a  proper  name. 

Thus  from  the  earliest  period  of  life  the  proper 
name  of  each  individual,  stamped  upon  the  mind 
while  it  is  in  the  act  of  accomplishing  its  first  opera- 
tions, becomes  incorporated  with  its  substance,  and 
becomes  for  the  individual  and  his  fellows  the  social 
characteristic  by  means  of  which  he  passes  through 
life.  This  characteristic  he  leaves  to  his  successors 
as  a  hereditary  patrimony,  and  they  in  their  turn 
transmit  it  to  their  descendants  with  the  proper  attri- 
butes of  genealogy. 


DEVELOPMENT  OF  THE  NOTION  OF  PERSONALITY.   24 1 

These  first  acquisitions  once  made,  the  child,  while 
conscious  that  he  can  outwardly  express  his  emotions 
and  desires,  that  he  has  a  proper  name  which  expresses 
his  personality,  only  achieves  the  various  degrees  of  his 
further  perfectionment  by  a  series  of  endeavours.  At  first 
he  stammers  out  his  first  desires  by  means  of  incorrect 
expressions,  a  rudimentary  attempt  made  up  of  common 
words.  He  understands  the  appeals  that  are  made  to  him, 
and  knows  when  they  are  addressed  to  his  personality. 
In  an  objective  excitation  from  without  he  perceives 
that  his  name  is  pronounced,  and  that  he  is  addressed. 
But  at  the  same  time  a  very  remarkable  fact  may  be 
observed,  which  shows  in  a  simple  manner  the  phases 
through  which  the  notion  of  personality  passes  before 
arriving  at  its  period  of  complete  solidification  in  the 
mind.  In  following  these  phases  step  by  step  we  per- 
ceive that  the  child  in  his  means  of  extrinsic  expression, 
only  by  degrees  gives  up  the  primordial  characteristics 
of  objectivity  which  mark  the  first  periods  of  his  de- 
velopment. 

Thus  young  children,  about  their  second  and  third 
years,  in  the  regular  course  of  their  development  speak 
as  they  feel.  They  are  accustomed  to  see  themselves 
as  a  body  which  has  an  external  form,  and  occupies  a 
determined  position  in  space.  Their  name  itself  is  not 
as  yet  completely  assimilated  by,  and  incarnated  in 
them,  as  the  concrete  expression  of  their  entire  being. 
They  still  preserve  a  certain  degree  of  objectivity ;  in 
the  primitive  form  of  their  language  they  speak  of 
themselves  in  the  third  person,  as  though  the  matter 
concerned  some  one  who  was  a  stranger  to  them,  mani- 
festing  their    emotions   or    desires    according    to   this 


242  THE   BRAIN  AND   ITS  FUNCTIONS. 

simple  formula :  "  Paul  wishes  for  so  and  so,  Paul  has 
a  pain  in  such  or  such  a  place." 

Little  by  little,  in  the  natural  progress  of  develop- 
ment which  is  going  forward,  the  child,  living  in  an 
attentive  medium,  and  automatically  hurried  along  in 
the  current  of  conversation,  makes  one  step  more  in 
the  way  of  his  intellectual  perfectionment. 

He  already  knows  that  his  personality  has  a  proper 
qualification.  He  knows  how  to  recognize  this  when 
it  is  mentioned,  and  turns  his  head  and  eyes  when  his 
name  is  pronounced  ;  and  his  language,  moreover,  as  has 
just  been  said,  in  a  rudimentary  fashion  makes  use  of 
the  impersonal  formula.  It  is  only  little  by  little,  and 
as  it  Avere  by  the  incessant  action  of  a  continual 
trituration,  that  he  can  be  taught  that  his  whole  per- 
sonality, constituting  a  unity,  may  take  another  abstract 
furm  besides  that  of  a  proper  name,  and  that  its 
equivalent  formula  is  represented  by  the  words  /,  nic. 
By  a  new  effort  of  abstraction  the  child,  who  receives 
into  his  voracious  mind  everything  that  is  thrust  into  it, 
unconsciously  receives  that  conventional  nutriment  fur- 
nished him  ready  prepared,  and  as  this  is  suitable, 
saves  trouble,  and  is  generally  employed,  he  appro- 
priates it,  makes  use  of  it,  and  by  degrees  employs  it 
in  current  conversation.  He  ends  by  substituting  the 
words  /  and  me  for  his  proper  name,  in  the  construction 
of  the  phrases  he  puts  together  according  to  the  rules 
of  grammar. 

Having  passed  through  this  phase  of  mental  develop- 
ment, which  is  only  completed  in  an  insensible  manner, 
by  means  of  a  daily  apprenticeship  which  is  in  force  at 
every    moment,    his    personality   accepts    the    regular 


DliVELOPMENT  OF  THE  NOTION  OF  PERSONALITY.   243 

methods  of  expressing  itself  outwardly  in  a  methodical 
and  regrular  manner,  which  shall  be  comprehended  by 
those  who  surround  him.  It  is  externally  clothed  in 
a  specific  denomination,  which  characterizes  it  as  a 
social  individuality,  by  the  proper  name  of  the  family 
from  which  it  springs.  It  is  confirmed,  grows  to  be 
part  and  parcel  of  social  intercourse,  becomes  incarnate 
— in  a  word,  a  precise  formula  which  is  accepted  by 
all  :  the  /  and  me  thus  becoming  the  extrinsic  gramma- 
tical manifestation  of  all  his  desires  and  emotions. 


CHAPTER  V. 

FUNCTIONAL  DISTURBANCE  OF   THE  NOTION   OF 
PERSONALITY. 

It  results  from  the  explanations  we  have  just  given 
that  the  notion  of  our  sentient  ego,  our  inner  person- 
ality, far  from  being  a  simple  and  unique  phenomenon, 
is  merely  the  result  of  a  series  of  organic  operations, 
which  combine  and  lend  each  other  a  mutual  support, 
but  which  are  nevertheless  capable  of  isolated  action. 
We  have  also  shown  that  this  notion  of  our  per- 
sonality, connected  with  the  life  of  the  organisms 
which  sustain  it,  cannot  maintain  itself  in  us,  always 
vivid  and  always  brilliant,  like  a  burning  fire,  except 
under  the  express  condition  that  it  shall  be  incessantly 
kept  alive  by  the  vital  forces  of  the  elements  which 
concur  to  produce  and  maintain  it.  As  it  is  dependent 
upon  the  oscillations  of  the  substratum  which  supports 
it,  it  is  liable  to  become  languid,  to  rise  and  fall  with 
this.  We  shall  now  endeavour  to  give  a  sketch  of  these 
different  vicissitudes. 

Thus  it  is  sometimes  the  peripheral  regions  of  the 
nervous  system  that  are  first  disturbed  in  their  function- 
ment,  and  thus  induce  a  morbid  slackening  in  the 
evolution  of  the  processes  of  the  central  regions. 

Sometimes,  on  the  contrary,  it  is  the  central  regions 


DISTURBANCE  OF  THE  NOTION  OF  PERSONALITY.    245 

which  are  engaged,  either  by  congestions  or  b)'  sudden 
arrests  in  the  course  of  the  blood  in  their  plexuses ; 
phenomena  which  in  the  first  case  lead  to  exaggerations 
of  the  personality,  in  the  second  to  transient  obtuse- 
ness,  loss  of  consciousness,  etc. 

In  the  first  case  we  meet  with  patients  (otherw^ise  pre- 
Jisposed)  attacked  by  anaesthesia  of  the  skin,  in  whom 
sensory  excitations,  instead  of  developing  in  the  sen- 
soriuin  the  habitual  reactions  which  result  from  contact 
with  the  external  w^orld,  cease  to  react.  Then  we  see  a 
series  of  delirious  conceptions  of  a  peculiar  kind  occur 
in  them  ;  the  process  of  personality,  deprived  of  its 
elementary  materials,  naturally  undergoes  an  arrest  of 
development.  Thus  they  think  they  have  lost  their 
personality,  that  they  are  changed  into  animals,  that 
they  have  become  inanimate  things — a  lump  of  clay, 
glass  or  butter — that  they  are  no  longer  alive.  An 
anaesthetic  patient  described  by  Michea,  said  that  his 
body  had  been  changed,  and  that  he  had  been  trans- 
formed into  a  machine  :  "  You  see,"  he  said  "  that  I  no 
longer  have  a  body."  Another  insisted  that  he  was 
dead  from  head  to  feet  *  The  elder  Foville  reports  the 
case  of  an  old  anaesthetic  soldier  who  said  that  he  had 
been  long  dead.  When  anyone  asked  after  his  hea.lth, 
he  would  say :  "  How  is  Pere  Lambert,  do  you  ask  ? 
He  is  dead.  He  was  killed  by  a  bullet.  What  you  see 
is  not  he  ;  it  is  a  machine  they  have  made  to  resemble 
him."  In  speaking  of  himself  he  never  said  me  but 
that, 

A  lady  affected  by  emotional  exitement,  whom  I  have 
had  occasion   to  observe,  and  who  was  similarly  anaes- 

*  Michea,  Annales  "Medico-psychol."  1856,  p.  249. 


246  THE  BRAIN  AND   ITS  FUNCTIONS. 

thetic,  has  told  me  she  no  longer  felt  anything  surround- 
ing her,  that  she  was  in  space,  that  her  body  no  longer 
possessed  weight,  and  that  she  was  on  the  point  of  flying 
away. 

The  surgeon  Baudeloque,  at  the  last  period  of  his 
life,  had  lost  consciousness  of  the  existence  of  his  body. 
If  he  were  asked  :  **  How  is  your  head  ? "  he  would 
answer:  "My  head!  I  have  none."  If  he  were  asked 
to  hold  out  his  hand  and  have  his  pulse  felt,  he  would 
say  that  he  did  not  know  where  it  was.  He  wished  one 
day  to  feel  his  own  pulse ;  they  placed  his  right  hand 
over  his  left  wrist,  and  he  then  asked  if  it  were  really 
his  own  hand  he  felt.* 

When  the  central  regions  of  the  nervous  system 
are  engaged  in  their  essential  constitution,  the  most 
interesting  disturbances  may  take  place  in  connection 
with  the  processes  of  the  notion  of  personality ;  these 
disturbances  being  different,  according  as  the  organic 
conditions  of  the  substratum  differ  as  regards  erethism 
or  collapse  of  the  cerebral  cells,  and  as  regards  acceler- 
ation or  slackening  of  the  blood  circulating  in  their 
plexuses. 

Thus  in  the  congestive  period  of  general  paralysis, 
when  the  elements  of  the  sensoriinn,  suffering  from  the 
most  intense  circulatory  super-activity,  receive  nutrient 
materials  in  excess,  they  are  by  this  means  impelled, 
like  all  the  other  histological  elements  of  the  economy, 
to  develop  their  peculiar  vitality  in  an  exaggerated 
manner.  They  then  assume  a  condition  of  exaltation, 
and   soon    develop   a   species  of   continuous  erethism, 

•  Quoted  from  Michda,  loc.  cit.,  and  "  Bibliothfeque  Mddicale,"  1809,  vol. 
Xvii. 


DISTURBANCE  OF  THE  NOTION  OF  PERSONALITY.    247 

while  the  physiological  function  they  consequently 
accomplish  by  ho  means  increases  in  an  equal  proportion. 
Thus  it  is  that  in  this  congestive  period  the  normal 
process  of  the  evolution  of  personality  is  exaggerated 
in  so  characteristic  a  manner.  At  this  period,  indeed, 
the  personality  of  the  individual  is  raised  several 
degrees  above  its  normal  pitch.  It  extends,  enlarges,* 
swells  out,  with  the  morphological  elements  upon  which 
it  lives,  and  the  patient,  hurried  into  that  fatal  cycle, 
feels  himself  richer,  greater,  stronger  than  he  was 
before.  He  speaks  of  himself,  his  physical  health, 
which  is  splendid,  of  the  riches  he  has  accumulated,  of 
his  social  importance,  which  is  immense — he  has  become 
a  king,  an  emperor,  a  pope,  etc. 

Under  contrary  conditions,  when  the  plexuses  of  the 
scnso7'ium  no  longer  receive  a  sufficient  quantity  of 
blood,  as  regards  their  assimilative  properties,  inverse 
phenomena  are  produced. 

The  elements  of  the  sensoriiirn  are  affected  v/Ith  a 
species  of  general  torpor  which  causes  their  vital 
energies  to  sink  below  their  normal  pitch,  and  they 
accordingly  exhibit  that  general  condition  of  diffused 
languishing  of  the  mental  forces,  in  which  the  processes 
of  personality  are  only  manifested  in  a  dull,  vague,  and 
diffuse  manner.  The  patients,  then  a  prey  to  certain 
forms  of  melancholy  with  stupor,  present  a  more  or 
less  complete  passivity,  an  apathy  and  profound  in- 
difference for  all  that  comes  in  contact  with  them  ; 
and  usually  this  torpid  condition  is  only  the  return 
effect   of  a   sort  of   anaesthesia  of  the  central   regions 

*  I  have  seen  a  patient,  in  the  congestive  stage  of  general  paralysis,  who 
assured  me  every  morning  that  he  had  grown  a  foot  hisrher. 


248  THE  BRAIN   AND   ITS   FUNCTIONS. 

which  goes  hand  in   hand  with  that  of  the  peripheral 
regions.* 

There  is  still  another  series  of  morbid  phenomena  in 
which  the  notion  of  personaHty,  and  consciousness  of 
the  external  world  may  be  suddenly  suspended  by  the 
effect  of  a  momentary  arrest  of  the  circulation  in  the 
plexuses  of  the  seiisoriiim. 

We  now  know,  thanks  to  the  labours  of  modern 
physiology,  that  intra-cephalic  circulatory  disturbances 
are  frequent  in  epileptics,  and  that  at  the  moment  of 
the  attack  the  loss  of  consciousness  is  produced  by  a 
spasm  of  the  vessels,  which  interferes  with  the  course 
of  the  blood  throup;h  the  cerebral  substance.  It  some- 
times  happens  that  these  circulatory  disturbances,  far 
from  taking  place  throughout  all  the  extent  of  the 
regions  of  the  sensoidum,  as  at  the  moment  of  the  great 
epileptic  attacks  with  complete  loss  of  consciousness, 
exercise  their  influence  only  within  limited  regions  of 
the  cerebral  substance.  There  are  then  local  arrests 
of  circulation  in  certain  cell-territories,  which  are  for 
the  moment  in  a  state  of  collapse — true  partial 
ischsemias  —  while  in  others  the  cerebral  activity 
continues  its  function  in  an  independent  manner. 
We  see  individuals,  as  if  in  a  state  of  somnambulism, 
act  unconsciously,  commit  extravagant  actions,  even 
crimes,  without  having  any  conscious  idea  of  the  things 
of  the  external  world  ;  and  at  the  end  of  several  hours, 
or  even  of  several  days,  emerge  from  this  condition  of 

*  In  a  patient  affected  with  melancholia  with  prolonged  stupor  ending  in 
death,  I  succeeded  in  discovering  a  most  characteristic  condition  of  anaemia  of 
the  cerebral  substance,  which  was  as  it  were  washed  clean  and  deprived  of 
sanguine  materials. 


DISTURBANCE  OF  THE  NOTION  OF  PERSONALITY.    249 

partial  stupor  of  their  sensormm,  quite  astonished  and 
stupined  by  the  words  they  have  pronounced  and  the 
deeds  they  have  done  during  this  period  of  interregnum 
of  their  conscious  personahty  (unconscious  aHenations).* 

Finally,  we  may  remember  that  the  notion  of  our 
personality,  which  in  its  constitution  and  its  very  exist- 
ence is  under  the  jurisdiction  of  the  organic  machinery 
ii  the  midst  of  which  it  lives,  is  regularly  eclipsed  every 
twelve  hours,  when  the  cerebral  cells  relapse  into  the 
condition  of  sleep. 

The  cerebral  cell,  in  fact,  like  the  peripheral  cell 
(sensorial  cells  of  the  retina),  becomes  fatigued  at  the 
end  of  a  certain  period  of  activity  ;  its  sensibility  be- 
comes more  or  less  rapidly  dulled.  It  is  fatigued,  and 
perforce  falls  into  a  state  of  collapse,  which  is  nothing 
but  physiological  sleep.  At  this  period  it  ceases  to 
attract  blood  to  it,  the  circulation  slackens,  and  in  pro- 
portion as  the  period  of  sleep  becomes  better  and 
better  marked,  and  loss  of  conscioiLsness  of  surrounding 
circumstances  occurs,  the  notion  of  oiir  personality  2X  the 
same  time  grows  dull,  and  finally  becomes  extinct,  and 
this  in  a  more  or  less  complete  manner,  according  to  the 
temperament  and  habits  of  each  person. 

*  See  the  cases  of  transitory  mania  reported  in  my  work  on  the  "Cerebra 
P.eflex  Actions,"  p.  137. 


BOOK    II. 

PHASE   OF   PROPAGATION   OF  THE   PROCESSES   OF 
CEREBRAL  ACTIVITY. 


CHAPTER   I. 

DISSEMINATION  OF  SENSORIAL  IMPRESSIONS  IN  THE 
PLEXUSES  OF  THE  PSYCHO-INTELLECTUAL  SPHERE. 
GENESIS  OF  IDEAS. 

We  have  already  se^n  that  sensorial  impressions,  once 
received  into  the  different  regions  of  the  cortical  peri- 
phery, become  dispersed  in  the  plexuses  of  the  sensormiUy 
which  constitutes  for  them  a  vast  field  of  projection, 
and  that,  pursuing  their  course  from  this  point  onwards, 
they  enter  into  particular  relations,  some  with  the 
sphere  of  psychical,  others  with  that  of  purely  intel- 
lectual, activity.  In  these  cerebral  regions  they  find 
the  last  stage  of  their  long  migrations  through  the 
organism.  There  they  are  concentrated  and  trans- 
formed, and,  under  new  forms,  having  become  intellec- 
tiialized  excitations  of  the  psycho-intellectual  sphere, 
hhey  constitute  the  fundamental  elements  of  all  the 
piienomena  of  cerebral  life. 


DISSEMINATION    OF   SENSORIAL   IMPRESSIONS.      2$  1 

There,  in  fact,  these  same  sensorial  excitations, 
incarnated  in  the  living  cell,  become  perpetuated  as 
persistent  excitations  ;  to  become,  as  it  were,  durable 
memorials  of  the  first  impression  that  gave  birth  to 
them.  There  they  repose,  in  those  infinite  labyrinths 
of  the  psycho-intellectual  sphere  where  they  live, 
always  alert,  always  brilliant,  like  faithfully-kept  ar- 
chives of  the  past  of  our  intellect  and  emotions.  There 
they  form  tliat  common  fund  of  ancient  memories, 
accumulated  from  our  earliest  years,  which  gives  birth  to 
those  fiuidamcjital-ideas  which  we  always  carry  within 
us,  and  which  are  but  radiations  from  the  external 
world,  that  have  previously  been  impressed  upon  us. 
They  have  lived  with  us  for  long  years,  and  have 
assumed  in  a  manner  an  independent  existence,  like 
foreign  grafts  implanted  in  our  substance.  The  ideas 
and  emotions  which  are  nearest  to  us  are,  then,  only 
direct  reflexions  and  prolonged  repercussions  of  the 
external  world  that  have  impressed  us  during  our 
course  through  life  ;  and  this  subtle  operation,  which 
commences  with  the  earliest  phases  of  our  existence,  is 
perpetuated,  and  perpetuates  itself  incessantly,  by  an 
incessant  participation  of  the  brain's  own  activity. 

Each  sensorial  impression  that  affects  us  leaves  a 
record,  a  specific  memory  ;  and  it  is  this  posthumous 
memory  of  the  absent  object  that  continues  to  vibrate, 
that  perpetuates,  vivifies,  reinforces  itself  by  means  of 
excitations  of  the  same  pitch,  which  communicate  to  it 
a  new  freshness  when  it  begins  to  grow  feeble.  The 
origin  and  permanence  of  our  ideas,  as  of  our  emotions, 
depend  upon  this  daily  maintenance  of  persistent  im- 
pressions. 


252  THE  BRAIN  AND   ITS   FUNCTIONS. 

If,  indeed,  we  inquire  profoundly  into  the  genealogy 
of  each  of  these  in  particular — if  we  submit  each  to  a 
series  of  elementary  analyses,  decomposing  it  into  its 
primary  elements,  we  shall  always  find  as  the  ultimate 
result,  at  the  bottom  of  the  crucible,  that  our  ideas,  like 
all  our  emotions,  are  reducible  to  a  sensorial  impression, 
as  the  fundamental  condition  of  their  occurrence. 
This  sensorial  impression  is  at  the  bottom  of  all  our 
ideas,  all  our  conceptions,  though  it  may  at  first  conceal 
itsef  in  the  form  of  a  binary,  ternary,  quaternary 
compound ;  and,  on  our  methodically  pursuing  the 
inquiry,  it  is  easily  recognizable — ^just  as  a  simple 
substance  in  organic  chemistry  may  always  be  sum- 
moned to  appear,  if  we  sit  down  with  the  resolution 
to  disengage  it  from  all  the  artificial  combinations 
which  hold  it  imprisoned.* 

*  The  ideas  of  time  and  space,  which  philosophers  have  so  long  considered 
irreducible,  are,  however,  decomposable  by  analysis  into  simple  elements  whioh 
connect  them  with  the  regular  processes  of  cerebral  activity. 

Thus  the  notion  we  acquire  of  space  is  directly  derived  from  that  of  muscular 
activity.  It  is  by  the  notion  of  the  amount  of  the  effort  made  to  change  our 
position. that  we  acquire  the  notion  of  the  road  passed  over,  and  of  its  length. 
It  is  by  steps  that  blind  men  judge  of  the  distance  from  one  place  to  another, 
and  thus  acquire  the  notion  of  space.  It  is  thus  that  we  successively  appre- 
ciate mentally  the  space  occupied  by  a  yard,  a  mile,  several  miles,  etc.;  and 
we  finally  arrive  at  the  conception  of  the  immensity  of  the  interplanetary 
spaces.  It  is  therefore  the  data  we  have  acquired  from  objective  nature  that 
preside  over  the  construction  of  our  notion  of  space. 

The  same  holds  good  for  the  notion  of  time.  It  is  a  very  co-nplex  process 
into  which  many  factors  enter,  and  above  all  the  rcg'stry  of  daily  facts.  Thus 
as  regards  the  appreciation  of  the  hours  of  the  d  ly,  we  refer  to  the  intensity 
of  the  brightness  of  day,  and  the  repetition  of  habitual  incidents,  and  to  many 
conditions  of  the  medium  surrounding  us  which  periodically  occur  at  a  given 
moment.  We  recognize  months  and  years,  by  the  facts  of  our  memory  and 
notes  which  register  what  we  have  done.  This  is  so  real,  that  when  the 
elements  of  the  sensoriutn  are  disturbed,  when  the  memory  becomes  impaired 
as  regards  the  retention  of  recent  facts,  the  notion  of  time  disp.ppears.     A  great 


GENESIS   OF   IDEAS.  2^S 

All  our  ideas  and  emotions  originate  then,  physiologi- 
cally, in  an  external  phenomenon  which  is  incarnated  in 
us,  and  perpetuates  itself  as  a  remembrance ;  and  it  is 
thus  that  our  ideas,  like  our  remembrances,  live  in  the 
life  of  the  organic  substratum  that  supports  them,  and 
with  it  undergo  all  the  oscillations  that  may  affect  it. 

Thus  by  means  of  the  calling  into  activity  of  the 
nerve-cell  with  all  its  intrinsic  and  extrinsic  attributes, 
the  sensorial  impression  imprinted  upon  it  becomes  an 
tdea,  that  is  to  say,  a  remembrance  of  the  absent  object. 
It  is  propagated  to  a  distance  by  means  of  anastomotic 
plexuses,  and  is  thus  transformed,  by  cell  after  cell,  into 
a  progressive  and  radiating  impression. 

Thus,  by  means  of  these  connections,  our  ideas  are 
associated,  grouping  themselves  methodically  into  con- 
temporary reminiscences,  appealing  one  to  another, 
when  the  first  link  of  the  chain  has  been  struck ;  pre- 
senting themselves  again  in  an  irregular  and  disconnected 
manner  when,  abandoning  the  direction  of  our  mind,  we 
let  it  run  wild,  as  it  is  termed  ;  when  we  give  audience  to 
our  thoughts,  that  is  to  say,  when  we  leave  tlic  auto- 
matic activities  of  our  cerebral  cells  to  exercise  them- 
selves according  to  their  natural  propensities  and  ap[)cal 
to  one  another  according  to  their  natural  affinities. 

It  is  by  means  of  this  organic  mechanism  that  movc- 
m.ent  and  life  are  incessantly  spread  through  the  plexuses 
of  the  cerebral  cortex  ;  that  excitations  of  all  kinds 
spring  up  in  their  minute  structure  on   the  arrival  of 

number  of  lunatics  who  have  been  for  several  years  in  asylums,  take  no  note  of 
the  time  that  passes,  and  make  considerable  mistakes  respecting  this  ;  they  say 
they  have  been  shut  up  for  five  or  six  years,  when  the  time  of  their  entry  into 
the  establishment  dates  back  as  much  as  fifteen  or  twenty  years. 


?54  THE   BRAIN   AND    ITS   FUNCTIONS. 

external  impressions  ;  that  the  materials  of  the  past 
become  associated  with  recent  ideas  and  impressions, 
and  that,  in  a  word,  those  marvellous  phenomena,  so 
instantaneous  and  so  varied,  presented  by  the  activity 
of  the  brain,  are  developed  in  presence  of  the  conscious 
personality,  which  assists,  as  a  spectator,  at  their  evolu- 
tion, without  being  able  to  direct  the  movement  which 
is  accomplished,  and,  strange  to  say,  with  the  idea  that 
it  is  regulating  them. 

We  generally  imagine  that  we  ordain  the  direction  of 
our  ideas  into  any  desired  channel,  and  that  we  can 
govern  their  evocation.  We  do  not  usually  perceive 
that,  while  we  imagine  we  are  leading  our  ideas  in  one 
direction,  we  are  unconsciously  obeying  the  second  phase 
of  a  movement  of  which  the  first  has  already  taken 
place. 

I  imagine  that  I  think  of  an  object  by  a  spontaneous 
effort  of  my  mind  ;  it  is  an  illusion — it  is  because  the 
cell-territory  where  that  object  resides  has  bee.i  previ- 
ously set  vibrating  in  my  brain.  I  obey  when  I  think 
I  am  commanding,  merely  turning  in  a  direction  towards 
which  I  am  unconsciously  drawn.  A  phenomenon  quite 
analogous  to  the  conjuring  trick  of  forcing  a  card  takes 
place  in  this  instance  ;  the  conjuror  forcing  us  uncon- 
sciously to  take  a  card,  while  letting  us  imagine  we  have 
a  liberty  of  choice. 

Sensorial  excitations,  once  they  are  disseminated  in 
the  plexuses  of  the  cortical  substance,  continue,  as  we 
have  already  several  times  said,  the  movement  com- 
menced by  their  contact  with  the  external  world.  The 
process  in  evolution  pursues  its  course,  and  then  they 
are  distributed — some  to  the  sphere   of  psychic  activity, 


GENESIS   OF  IDEAS.  255 

others  to  that  of  intellectual  activity  proper.     We  shall 
now  pursue  the  study  of  them  into  these  two  regions.* 

*  Peripheral  impressions  do  not  all  arrive  at  the  sensorium  with  equal  rapidity 
even  in  the  same  individual.  In  the  sensitive  nerves  the  rapidity  of  transmis- 
sion has  been  variously  estimated.  It  oscillates  according  to  different  authors, 
between  24  and  26  metres  a  second.  It  is  modified  by  several  influences, 
cold  for  instance  and  the  electro-tonic  condition.  It  is  probable  that  it  is  not 
uniform,  and  that  it  diminishes  in  the  ratio  of  the  distance  of  its  origin. 
(Hermann,  "Physiology,"  p.  319.) 

Mach  has  endeavoured  comparatively  to  determine  the  minimum  time  for  the 
convKsion,  within  the  brain,  of  an  impression  into  a  motor  excitation.  For 
visual  impressions  the  rapidity  of  transmission  is  ©•0472  ;  for  tactile  impressions 
©■029;  for  auditory  impressions  o'oi6.  That  is  to  say,  of  all  impressions 
auditory  are  most  rapidly  perceived.  ("Annales  Medico-psychologiques," 
1869,  vol.  ii.  6,  441.) 

On  the  other  hand,  astronomers  have  long  designated  under  the  name  "indi- 
vidual coefficient,"  that  allowance  which  must  be  made,  in  correcting  formulas, 
for  the  unequal  rapidity  with  which  different  observers  perceive  the  occurrence 
of  the  same  celestial  phenomenon.  We  know,  in  fact,  that  when  several  persons 
are  charged  with  the  notation  of  the  exact  time  of  the  meridian  passage  of 
a  star,  there  is  never  perfect  synchronism  between  all  their  observations.  The 
transmission  to  the  sensorium  of  the  luminous  impression,  and  its  conversion 
into  a  reflex  motor  excitation,  takes  place  with  unequal  rapidity  in  different 
persons.  This  leads  us  to  the  conclusion  that,  as  regards  intellectual  operations, 
there  is  a  physiological  habit  proper  to  each  individual  ;  that  there  are  persons 
slow  to  see,  slow  to  comprehend  and  to  react,  just  as  there  are,  as  regards  the 
phenomena  of  somatic  progression,  persons  slow  to  move,  and  lazy  in  walking. 


CHAPTER  11. 

EVOLUTION   AND   TRANSFORMATION   OF   SENSORIAL 

IMPRESSIONS. 

Evolution  of  Seitsitive  Impressions. — Sensitive  impres- 
sions in  general  comprehend  not  merely  impressions 
of  touch,  contact,  and  pressure  of  bodies,  but  also 
those  which  give  us  the  idea  of  temperature,  and  that 
of  the  activity  of  our  muscles.  They  are  designed, 
either  isolatedly  or  simultaneously,  to  play  a  principal 
part  in  the  phenomena  of  cerebral  activity  proper ; 
forming,  as  has  been  explained,  an  enormous  contingent 
of  connate  excitations  which  are  distributed  in  the 
domain  of  psychical  activity  proper  as  well  as  that  of 
intellectual  activity.* 

Radiating  from  the  central  regions  of  the  optic  thalami 
which  represent  the  very  centre  of  the  brain,  they  do 
not  as  yet  appear  to  have  a  very  clearly  defined  localiza- 
tion, as  regards  their  ultimate  distribution.  Indeed,  the 
fibres  that  radiate  from  the  median  centre  appear  as 
though  they  must  distribute  them  equally  throughout 
the  different  zones  of  the  cerebral  cortex. 

*  The  part  played  by  sensitive  impressions  in  the  phenomena  of  cerebral 
activity  is  so  important,  as  regards  the  physiological  stimulation  they  develop, 
that  when,  in  consequence  of  amputation  of  the  limbs,  they  have  long  ceased 
to  stimulate  the  brain,  the  hemisphere  that  has  ceased  to  receive  them  under- 
goes a  correlative  atrophy,  in  consequence  of  the  cessaiion  of  their  influx. 


EVOLUTION   OF   SENSORIAL  IMPRESSIONS.        257 

The  contingent  of  sensitive  elements  specially  reserved 
for  distribution  in  the  field  of  psychical  activity,  as  we 
have  defined  it,  is  represented  by  all  those  agglomera- 
tions of  sensitive  excitations  which,  drawn  from  all  the 
sensitive  points  of  the  organism,  are  conducted  towards 
the  central  regions  by  the  centripetal  channels. 

These  agglomerated  sensitive  elements,  incessantly 
vibrating  with  one  accord,  incessantly  active,  become 
in  the  sensorhiin  the  elements  constituting  our  inner 
personality,  our  sentient  unity.  This  is  the  special  part 
played  by  sentient  impressions  as  regards  psychical 
activity  proper  ;  and  we  see  what  an  important  part  it 
is.  they  being  the  keystones  of  the  whole  edifice  of  our 
mental  activity,  since  they  produce  by  their  synthesis 
the  notion  of  a  living  individuality  in  exercise. 

Genesis  of  tJie  Notion  of  Happiness  and  Unhappiness. — 
Sensitive  impressions  are  again  reverberated  in  the 
sensoriiun  in  a  very  peculiar  manner,  exciting  in  it 
conditions  which  depend  on  them  alone. 

Thus  from  that  pre-established  consensus  between  the 
peripheral  and  central  regions  of  the  nervous  system, 
on  which  we  have  so  strongly  insisted,  this  very  remark- 
able consequence  results  :  that  the  special  condition  of 
the  sensitive  nerves  (when  afi"ected  by  impressions 
which  gratify  their  natural  sensibility)  is  reflected 
upon  the  sensoriiun,  and  there  develops  a  species  oi 
concord,  b}'  means  of  which  it  enters  into  unison  with 
them. 

When  a  warm  atmosphere  refreshes  our  skin  with 
gentle  perspiration,  when  comfortable  repose  revives  our 
strength  and  restores  to  our  fatigued  muscles  and  aching 
joints  their  pristine  flexibility  and  elasticity,  we  say  that 


258  THE   BRAIN   AND   ITS  FUNCTIONS. 

we  are  in  a  special  condition  of  comfort—  that  this  has 
given  \xs>  pleasiLve. 

This  word  pleasure  characterizes  a  special  state  of 
our  seiisoriiiin,  a  peculiar  pitch  of  the  sensibility,  which 
is  desired  by  every  one,  and  which  thus  becomes  a 
specific  mode  of  existence  of  the  sensorhmi^  which  fixes 
and  perpetuates  itself  in  us  as  a  memory  and  a  hope. 
It  is  a  kind  of  specific  sentiment,  a  species  of  standard 
sentiment  with  which  we  compare  the  greater  number 
of  the  impressions  that  come  to  be  reflected  in  us  ; 
so  that,  by  extension,  the  notion  of  the  pleasure  of  our 
gratified  sensitive  nerves  insensibly  becomes  subjective, 
to  be  transformed  into  the  notion  of  happiness.  It 
results  from  this  mental  evolution  that  when  any  act 
whatever  of  the  human  activity  is  judged  of  by  us,  we 
say  that  it  is  good,  because  it  has  produced  in  the 
sphere  of  our  moral  sensibility  an  impression  equivalent 
to  that  produced  in  the  domain  of  physical  sensibility 
by  a  sensorial  impression  which  has  given  us  pleasure. 
And,  inversely,  whatever  wounds  or  offends  our  physical 
sensibility — whatever  gives  us  pain — places  our  senso- 
riiLin  in  very  different  conditions  from  the  foregoing,  and 
thus  becomes  the  subjective  notion  of  unhappiness,  to 
which  we  refer  all  the  miseries  of  our  moral  sensibility. 

In  the  domain  of  intellectual  activity  proper,  sensitive 
impressions  also  come  to  be  of  the  utmost  importance. 

United  with  the  correlated  impressions  that  emanate 
from  the  minute  structure  of  our  muscles  when  in  action, 
they  make  part  and  parcel  of  a  number  of  complex 
notions,  by  which  the  understanding  profits,  and  which 
are  incessantly  laid  under  contribution  without  our 
having  any  clear  consciousness  of  the  fact. 


EVOLUTION   OF   SENSORIAL   IMPRESSIONS.        259 

It  is  chiefly  tactile  impressions  that  form  the  special 
contingent  destined  to  provoke  the  reactions  of  the 
intellectual  sphere. 

Radiated  from  the  extremities  of  the  peripheral 
plexuses,  gifted  with  a  special  organization  (sensitive 
papillae,  tactile  corpuscles  of  Pacini),  these  impressions 
furnish  the  intellect  with  a  number  of  notions,  not  very- 
numerous,  it  is  true,  but  very  precise,  respecting  the 
different  qualities  of  bodies  in  contact  with  them.  It  is 
by  means  of  them  that  we  form  our  judgments  respect- 
ing the  dimensions  and  surface-condition  of  external 
bodies,  and  respecting  their  motion,  temperature,  and  de- 
gree of  dryness  or  moisture.  It  is  by  means  of  them  and 
their  fellows  of  muscular  sensibility  that  we  are  informed 
of  the  expenditure  of  nerve-power  necessary  to  gauge 
the  weight  of  heavy  bodies,  to  lift  them,  and  indirectly 
acquire  a  precise  notion  of  their  volume  and  solidity. 

This  special  contingent  of  sensitive  elements,  by 
means  of  which  the  notion  of  human  personality  is 
developed  and  maintained,  and  by  means  of  which 
also  we  are  constantly  in  contact  with  the  things 
of  the  external  world — this  contingent,  I  say,  is  still 
destined  to  vibrate  in  harmony  with  all  the  mental 
faculties,  and  to  give  specific  bent  to  the  character 
of  the  individual,  as  well  as  to  the  creations  of  his 
mind.  We  may  say,  then,  that  a  greater  or  less 
degree  of  perfectionment,  and  a  greater  or  less  degree 
of  sensitive  power  in  the  sensitive  regions,  find  their 
counterpart  in  the  central  regions,  and  that  the  greater 
the  degree  of  physical,  the  greater  will  be  the  degree  of 
moral  sensibility. 

We    all    know   how  fine,    delicate,    and  sensitive    is 


260  THE   BRA.IN   AND   ITS   FUNCTIONS. 

the  skin  of  women  in  general,  and  particularly  of 
those  who  live  in  idleness  and  do  no  manual  work — - 
how  their  sensitive  nervous  plexuses  are  in  a  manner 
exposed  naked  to  exciting  agencies  of  all  sorts,  and 
how,  from  this  very  fact,  this  tactile  sensibility,  inces- 
santly awake,  and  incessantly  in  vibration,  keeps  their 
mind  continually  informed  of  a  thousand  sensations  that 
escape  us  men,  and  of  tactile  subtleties  of  which  we 
have  no  notion.  Thus  in  idle  women  of  society,  and 
men  with  a  fine  skin,  mental  aptitudes  are  developed 
and  maintained  in  the  direct  ratio  of  the  perfection- 
ment  and  delicacy  of  sensibility  of  the  skin.  The 
perfection  of  touch  becomes  in  a  manner  a  second 
sight,  which  enables  the  mind  to  feel  and  see  fine  details 
which  escape  the  generality  of  men,  and  constitutes  a 
quality  of  the  first  order,  moral  tact,  that  touch  of  the 
soul  (toucher  de  I'ame),  as  it  has  been  called,  which  is 
the  characteristic  of  organizations  with  a  delicate  and 
impressionable  skin,  whose  sensor  mm,  like  a  tense  cord, 
is  always  ready  to  vibrate  at  the  contact  of  the  slightest 
impressions. 

Inversely,  compare  the  thick  skin  of  the  man  of  toil, 
accustomed  to  handle  coarse  tools  and  lift  heavy  bur- 
dens, and  in  whom  the  sensitive  plexuses  are  removed 
from  the  bodies  they  touch  by  a  thick  layer  of  epithelial 
callosities,  and  see  if,  after  an  examination  of  his  intel- 
lectual and  moral  sensibility,  you  are  understood  when 
you  endeavour  to  evoke  in  him  some  sparks  of  those 
delicacies  of  sentiment  that  so  clearly  characterize  the 
mental  condition  of  individuals  with  a  fine  skin.  On 
this  point  experience  has  long  ago  pronounced  judg- 
ment, and  we  all  know  that  we  must  speak  to  every  one 


EVOLUTION   OF   SENSORIAL  IMPRESSIONS.       261 

in  the  language  he  can  comprehend,  and  that  to  en- 
deavour to  awaken  in  the  mind  of  a  man  of  coarse  skin 
a  notion  of  the  delicacies  of  a  refined  sentiment  is  to 
speak  to  a  deaf  man  of  the  deHciousness  of  harmony 
EJid  to  a  blind  man  of  the  beauties  of  colours."^ 

Evolution  of  Optic  Impressions. — The  luminous  vibra- 
tions, directly  transformed  into  nervous  vibrations  by 
the  peculiar  action  of  the  retina,  are  all  at  first  con- 
centrated in  the  grey  centres  of  the  optic  thalamus 
devoted  to  them,  and  radiated  thence,  chiefly  into  the 
antero-lateral  regions  of  the  cerebral  cortex.  They 
arrive  in  the  sensorium,  as  we  have  already  described, 
with  different  degrees  of  rapidity  in  different  indi- 
viduals,t  and  from  the  time  when  they  come  in  the 
morning  to  illuminate  the  nervous  plexuses  of  the  scn- 
soriiim  they  are  continuous,  and  by  their  incessant 
stimulation  during  the  period  of  waking  maintain  the 
activity  of  the  cerebral  cells  in  continued  erethism. 

The  luminous  undulations  which  thus  radiate  through 
the  brain  are   not  homogeneous  as  regards  their  ex- 

*  To  the  facts  we  have  already  cited  respecting  the  pathogenic  influence 
exercised  by  certain  anaesthesias  upon  the  genealogy  of  certain  forms  of  deli- 
rium, we  should  add  as  a  complement  the  following  observations  reported  by 
Dr.  Auzouy,  which  clearly  show  what  a  curious  influence  sensitive  impressions 
may  have  upon  psycho-intellectual  phenomena  in  general.  The  case  was  that 
of  a  young  man,  clever  and  rational,  who  suddenly  became  undisciplined  and 
rebellious  to  the  utmost  extent,  and  gave  himself  up  to  the  worst  tendencies, 
even  to  the  compromising  of  the  peace  and  honour  of  his  family.  Examina- 
tion showed  that  he  was  completely  anaesthetic.  During  his  stay  in  the  asylum 
he  successively  experienced  several  intermittent  phases  of  anaesthesia,  of  which 
the  appearance  manifestly  coincided  with  the  return  of  his  worst  instincts. 
When  sensibility  reappeared  in  the  skin,  moral  dispositions  contrary  to  the  pre- 
ceding were  observed  to  return  in  him,  together  with  a  very  clear  conscious- 
ness of  his  situation.  (Auzouy,  "Annales  Medico-psychol.,"  1859,  P-  535) 
Des  troubles /onctionnels  de  la  peau  et  de  V action  de  niectricite  chez  les  alienes. 

f  See  p.  255  (note). 


262  THE   BRAIN   AND   ITS   FUNCTION^. 

trinsic  characters,  and  do  not  equally  affect  the  different 
regions  of  the  cortex  in  which  they  are  distributed. 
Thus,  not  only  do  they  transmit  to  the  sensoriiLin  per- 
ceptions of  the  different  gradations  of  intensity  of  light, 
but  furnish  as  well  the  most  specific  notions  of  the 
colour  of  surrounding  objects.  There  are  thus,  in  fact, 
two  different  modes  in  which  the  elements  of  the  sen- 
soriiLin may  be  affected  ;  and  in  most  men  one  or  other 
of  these  modes  usually  predominates.  We  meet  with 
certain  organizations  which  from  this  point  of  view  are 
very  unequally  endowed.  Every  one  knows  that  if  all 
persons  with  the  gift  of  sight  have  the  faculty  of  being 
impressed  by  light,  all  have  not  the  faculty  of  perceiv- 
ing colours  in  an  equal  degree,  and  that  there  are 
persons  who  suffer  from  a  peculiar  form  of  blindness 
which  makes  certain  hues  virtually  non-existent  for 
them.*  We  all  know  that  certain  painters,  who  are 
gifted  in  the  highest  degree  with  that  natural  aptitude 
for  perceiving  in  a  complete  manner  the  different  grada- 
tions of  the  colour  of  objects,  can  give  to  their  works 
a  quite  unique  intensity  of  colour,  a  richness  of  tone 
which  they  draw  from  their  own  personality,  and  which 
their  less  gifted  rivals  can  neither  comprehend  nor 
imitate. 

Optic  impressions,  as   well  as   sensitive,  are  divided 
into   two    contingents  which  are  separately  distributed, 

*  Mr.  Black  saw  a  man  of  fifty  years  of  age  in  Glasgow  who  had  lost  his 
sight  when  two  months  old,  and  yet  learnt  by  dt^grees  to  distinguish  colours  so 
clearly  that  he  could  exercise  his  profession  as  a  dyer,  without  any  help,  for 
more  than  forty  years.  He  could  not  only  perfectly  appreciate  colours  and 
shades,  but  had  learnt  by  practice  to  give  the  stuff  a  lighter  or  darker  tint 
without  making  any  mistake.     ("Annales  Midico-psychol.,"  1848,  p.  414.) 

See  also  the  memoir  of  Earle  on  the  incapacity  for  distinguishing  colours. 

'Annales  Medico-psychoL,"  1846,  p.  217.) 


EVOLUTION   OF   SENSORIAL   IMPRESSIONS.        263 

either  in  the  sphere  of  psychical  or  the  sphere  of  intel- 
lectual activity. 

I.  Genesis  of  the  Notion  of  Beauty  and  Ugliness. 

The  particular  contingent  of  optic  impressions  des- 
tined to  be  distributed  in  the  sphere  of  psychical  activity 
appears  to  be  the  origin  of  that  faculty  by  which  we 
pronounce  as  to  the  beaitty  or  ugliness  of  the  thing  that 
impresses  us,  and  in  this  it  resembles  those  sensitive  im- 
pressions that  furnish  us  with  the  notion  of  happiness, 
by  means  of  a  regularly  accomplished  physiological 
process.  These  optic  impressions  are  similarly  the  fun- 
damental impressions  that  engender  in  us  the  notion 
of  the  beantifnl. 

These  optic  impressions,  indeed,  originating  as  they 
do,  like  those  of  general  sensibility,  in  the  peripheral 
regions,  do  not  ascend  into  the  sensoriiun  in  the  condi- 
tion of  atonic,  indifferent,  slightly-stimulating  impres- 
sions. They  carry  with  them  the  special  condition  into 
which  the  peripheral  plexuses  have  been  thrown  at  the 
moment  of  their  genesis,  and  the  simultaneous  notions 
of  concomitant  pleasure  or  pain.  When  an  agreeable 
spectacle  presents  itself  to  our  eyes,  our  retinas,  being 
impressionable  nervous  plexuses,  are  more  or  less 
directly  gratified  as  regards  their  natural  sensibility,  just 
as  when  an  agreeable  sensation  affects  our  sensitive 
nerves  ;  and  this  special  satisfaction  is  transmitted  to 
the  sensorinni,  thereby  producing  in  it  also  a  special 
vital  condition,  a  new  state  which  we  express  under  the 
denomination  of  a  sensation  of  beanty.'^ 

*  Thus  there  are  intrinsic  satisfactions  for  the  eves  as  well  as  the  ears. 
It  is  with  infinite  pleasure  that  we  all  salute  the  light  on  emerging  from 
obscurity ;   that  our  eyes  are  pleased  to  receive  the  primitive  rays  of  the  spec- 


264  THE   BRAIN   AND   ITS   FUNCTIONS. 

Th*^  subjective  notion  that  we  have  of  the  beauty  of 
tfiings  is  thus,  in  the  primitive  man,  who  knows  nothing 
of  either  the  subtleties  of  art,  or  the  casuistries  01  the 
different  schools,  or  the  code  of  amateurs,  fundamen- 
tally connected  with  the  memory  of  an  agreeable 
impression,  a  purely  visual  satisfaction  felt  by  the 
retina  when  agreeably  affected. 

Children  love  all  that  is  brilliant  and  that  glitters  in 
the  sun ;  the  inhabitants  of  northern  countries  and  cer- 
tain savage  tribes,  are  attracted  by  the  sight  of  objects 
of  a  vivid  colour,  and  tints  which  violently  affect  the 
sight.  These  are  the  rudimentary  forms  of  the  idea  of 
the  beautiful,  which  is  really  derived  from  a  primitive 
physical  impression.  It  is  only  by  degrees,  by  means 
of  the  participation  of  the  intellect,  the  culture  of  the 
judgment,  and  comparison,  that  this  first  notion  comes 
to  perfection  in  us,  and  becomes  a  rational  well-digested 
appreciation,  though  having  its  origin  in  a  physical 
impression  which  is  at  first  addressed  to  our  optic 
sensibility. 

Conversely  we  can  comprehend  that  those  things  which 
produce  on  the  retina  a  painful  impression,  which  are 
unpleasant  to  see,  are  also  those  which  produce  a  pain- 
ful im.pression  on  the  sensoidiim,  and  which  bring  with 
them  a  notion  the  reverse  of  the  former,  that  is  to  say 
that  of  ugliness. 

2.  Optic  impressions,  when  carried  up  to  the  scnso- 
rium,  not  only  excite  in  it  special  conditions  by  means 
of  which  the  notion  of  beauty  or  ugliness  is  naturally 

trum,  that  they  rejoice  in  the  magnificent  stained-glass  of  our  old  cathedrals 
when  the  sun  shines  through  them,  in  the  folds  of  rich  satin  stuffs,  the  multi- 
coiouied  reflexes  of  brilliant  flowers,  fireworks  or  coloursd  flames. 


EVOLUTION   OF   SENSORIAL  IMPRESSIONS.        265 

developed  in  us,  but  they  are  further  gifted  with  a  more 
intense  penetrative  power,  and  while  taking  upon  them 
a  thousand  forms  they  touch  and  set  vibrating  all.  the 
chords  of  our  emotivity. 

Thus  the  sight  of  a  landscape  in  full  sunshine, 
enamelled  with  flowers  of  a  thousand  hues,  and 
covered  with  green  meadows  w^ith  distant  horizons, 
develops  in  us  sentiments  of  satisfaction  which  gratify 
our  sensibility  and  cause  it  to  expand  ;  while  a  gloomy 
place,  shut  in  by  high  walls,  and  without  verdure,  sad- 
dens the  saisoriitin,  and  develops  in  us  a  very  legitimate 
sentiment  of  repulsion,  in  which  all  share.  Thus  these 
sentiments  of  attraction  and  repulsion  are  directly 
imposed  upon  us  in  consequence  of  the  perceived 
impression,  without  the  intervention  of  memory  or  of 
old  reminiscences. 

By  reason  of  those  mysterious  affinities  which  unite 
the  present  with  the  past,  as  regards  our  ideas  and 
emotions,  a  simple  appearance,  a  simple  optic  impres- 
sion, is  capable  of  reviving  old  memories,  and  according 
to  circumstances,  of  setting  in  vibration  all  the  different 
emotional  chords  that  it  touches  within  us. 

Thus  the  sight  of  an  external  symbol,  a  banner,  a 
standard,  a  flag,  is  capable  of  suddenly  exciting  in 
those  who  behold  and  salute  it,  the  most  diverse 
sentiments,  from  the  fact  that  its  appearance  awakes 
in  them  a  series  of  individual  reminiscences.  It  is 
by  the  sight  of  the  external  pomp  that  surrounds 
them,  the  display  of  gold  and  silver  embroideries,  of 
brilliant  uniforms,  that  the  possessors  of  authority  at 
all  times  and  in  all  places  have  sought  to  inspire  respect 
in  the  crowds  before  which  they  have  passed.  It  is  by 
^9 


266  THE  BRAIN  AND   ITS  FUNCTIONS. 

securing  the  passive  admiration  of  the  eyes  of  their 
dazzled  contemporaries  that  they  have  always  main- 
tained their  prestige.  It  is  for  the  gratification  of  the 
eye  that  human  beings  over  the  whole  surface  of  the 
globe  seek,  according  to  their  means,  to  ornament  their 
persons  and  appear  to  the  utmost  advantage  externally. 

It  is  by  the  lust  of  the  eye  that  we  are  all,  small  or 
great,  young  or  old,  rustics  or  citizens,  captivated  and 
allured  ;  for  it  is  always  our  eyes  that  are  first  charmed 
by  the  contemplation  of  physical  beauty;  and  the  most 
powerful  of  sentiments,  love,  destined  to  set  the  heart 
of  man  beating,  has,  as  a  general  rule,  its  sole  origin  in 
the  seduction  of  the  sight,  the  pleasure  of  the  eyes, 
which  ardently  desire  the  object  which  has  charmed 
them,  and  excited  the  spontaneous  awaking  of  all  latent 
delights. 

It  is,  moreover,  by  means  of  those  mysterious  links 
which  associate  optic  impressions  with  our  sentiments, 
that  our  former  emotions,  our  secret  affections  are 
awakened  and  maintained  by  the  sight  of  certain 
keepsakes.  Every  one  knows  what  a  sweet  consola- 
tion for  the  absent  are  the  features  of  a  beloved  person 
reproduced  by  painting  ;  how  certain  institutions,  cer- 
tain public  or  private  ceremonies  recurring  in  a  periodic 
manner,  certain  anniversaries,  are  similarly  calculated 
to  revive  in  us  former  emotions,  and  again  bring  us  into 
the  presence  of  the  persons  and  circumstances  that  have 
first  inspired  them,  recalling  the  periods  at  which  our 
emotions  have  been  set  in  movement. 

3.  Again,  in  the  sphere  of  purely  intellectual  pheno- 
mena, optic  impressions  play  a  very  important  part 
which  deserves  attention. 


EVOLUTION   OF   SENSORIAL  IMPRESSIONS.        26/ 

Tlijs,  either  alone  or  associated  with  their  excito- 
motor  fellows,  which  regulate  without  our  know- 
led^re  the  different  movements  of  accommodation  of 
the  eye,  they  permit  us  to  judge  of  the  distance,  the 
dimensions,  and  the  forms  of  different  surrounding 
objects.  Thus,  as  when  we  have  to  do  with  the  impres- 
sions of  sensibility  proper,  former  impressions  are 
associated  with  recent,  to  form  the  elements  of  com- 
parison. When  we  say  that  a  body  is  at  such  or 
such  a  distance  from  us,  there  is  a  reflex  action  of  the 
intelligence  which,  from  our  knowledge  of  the  object, 
and  the  manner  in  which  it  is  illuminated,  associates  a 
series  of  notions  previously  acquired  with  a  recent 
impression.  When,  as  regards  a  body  that  moves  trans- 
versely before  us,  we  judge  of  the  direction  of  this 
movement,  it  is  still  the  evocation  of  an  impression 
formerly  received  that  comes  to  be  annexed  to  a  recent 
impression. 

Thus  by  degrees  a  crowd  of  complex  notions  is 
created  in  the  mind  by  the  arrival  of  optic  impressions, 
and  their  preservation  in  the  state  of  persistent 
memories.  The  sense  of  sight  consequently  becomes 
one  of  the  most  fertile  sources  from  which  all  our  cere- 
bral activity  is  incessantly  fed.  It  is  optic  impressions 
again  that  with  their  acoustic  fellows  are  called  on  to 
play  such  an  important  part  in  the  artificial  culture  of 
the  mind,  both  in  the  mental  interpretation  of  graphic 
signs  in  the  action  of  writing  from  dictation,  and  in 
the  regular  tracing  of  such  characters  in  the  action  of 
writing  spontaneously.  They  are  also  the  introducers 
of  the  thoughts  of  others  into  our  minds,  when,  with 
cur  eyes  fixed  on  the  written  characters,  we  attach   to 


268  THE  BRAIN  AND   ITS   FUNCTIONS. 

each  of  these  characters  correlative  ideas  and  co-ordi.. 
nated  emotions.  They  thus  animate  these  silent  cha- 
racters, giving  them  Hfe  and  fixing  them  in  us  as  mate- 
rials designed  to  excite  in  the  mind  new  associations 
of  ideas,  and  the  most  varied  impressions. 

They  are  therefore,  in  fact,  the  most  powerful  agents 
that  stimulate  the  culture  of  the  psycho-intellectual 
sphere,  and  fertilize  its  activity.  They  permit  us  at 
once  to  receive  impressions  from  the  thoughts  of  others, 
by  means  of  written  words,  transmitted  to  a  distance, 
and  reciprocally  to  manifest  our  emotions  and  ideas  in 
a  manuscript,  form,  which  thus  becomes  the  manifest 
expression  of  the  different  states  that  they  pass  through. 

4.  The  important  part  that  optic  impressions  play 
in  the  functionmentof  mental  activity  leads  to  the  con- 
clusion that  when  they  are  wanting  there  will  be  a 
certain  disturbance  of  the  general  equilibrium,  which 
will  have  as  its  consequence  special  disturbances  of 
cerebral  functionment. 

Up  to  the  present  time,  the  mental  condition  of  the 
blind  has  not  been  studied  in  a  sufficiently  precise 
manner  to  permit  of  our  clearly  appreciating  the  modi- 
fications which  occur  in  the  character  or  fashion  of  their 
ideas,  under  the  influence  of  the  arrest  of  development 
of  their  optic  impressions.  Nevertheless,  we  may  say 
with  Dumont,  who  has  already  occupied  himself  with 
this  question,  that  the  influence  that  optic  impressions 
exercise  upon  the  play  of  the  cerebral  functions  is 
most  important,  and  that  a  certain  number  of  indi- 
viduals, whom  he  had  an  opportunity  of  observing, 
presented,  from  a  psychical  point  of  view,  changes  of 
temper   and   symptoms   of    melancholy,    all    the   more 


EVOLUTION   OF   SENSORIAL   IMPRESSIONS.        269 

marked  because  the  patients  were  incapable  of  dis- 
cerning day  from  night.* 

As  regards  such  phenomena,  Bouisson  has  observed 
a  most  remarkable  case.f  The  patient  was  a  young 
man  who  had  become  insane  in  consequence  of  a  double 
cataract,  with  incoherence  of  ideas,  complete  failure 
of  spontaneity.  Bouisson,  from  the  antecedents  of  the 
patient,  hit  on  the  happy  idea  of  performing  an  opera- 
tion. It  was  simultaneously  performed  in  both  eyes, 
by  couching,  and  a  few  days  afterwards,  when  optic  im- 
pressions reappeared  to  stimulate  regularly  the  scnsorimn 
of  the  patient,  and  vision  was  restored  to  him,  he  began 
to  utter  a  few  sensible  words,  his  mental  state  became 
progressively  better,  and,  at  the  end  of  a  i(t\N  weeks,  he 
left  the  hospital  capable  of  attending  to  his  own  wants. 

Baillarger  has  also  reported  analogous  facts.  Thus, 
he  cites  from  Whytt  the  case  of  a  patient  who,  if  his 
eyes  were  closed  by  another  person,  even  without 
sleeping,  fell  into  a  great  disorder  of  mind.  It  seemed 
to  him  that  he  was  transported  through  the  air,  and 
that  his  limbs  were  falling  off. 

In  a  patient  of  twenty-seven,  whom  he  observed  him- 
self, he  noticed  that  as  soon  as  she  shut  her  eyes,  she 
saw  animals,  fields,  and  houses.  "  I  several  times  closed 
her  lids  myself,"  he  says,  "and  immediately  she  men- 
tioned to  me  a  number  of  objects  that  appeared  to  her."J 

*  According  to  Dumont,  among  120  blind  persons,  excluding  those  who  are 
affected  with  appreciable  brain  lesions,  there  are  thirty-seven  with  intellectual 
disorders  varying  from  hypochondria  to  mania,  hallucination  and  dementia, 
(influence  of  blindness  on  the  intellectual  functions.)  "Moniteur  des  Hopi- 
tiiux,"  1857,  pp.  245  and  265. 

t  "  Bulletin  de  I'Academie  de  Medicine,"  8th  Oct.,  i860. 

X  Baillarger,  "  Annales  Medico-psychol.,"  1845,  pp.  22,  23.  (On  the  influ- 
ence of  the  state  intermediate  between  sleep  and  waking.) 


2/0  THE  BRAIN   AND   ITS   FUNCTIONS. 

Evolution  of  Acoustic  Impressions. — Acoustic  impres- 
sions, like  optic  impressions,  play  a  most  important 
part  in  the  sum-total  of  the  manifestations  of  mental 
activity.  Like  them,  they  are  incessant  during  the 
whole  diurnal  period,  and  by  their  uninterrupted  stimu- 
lation maintain  cerebral  functionment  in  a  perpetual 
condition  of  erethism.  They  are,  for  us,  the  natural 
vehicles  of  the  notion  of  sound  and  harmony,  while,  at 
the  same  time,  they  are  the  generating  elements  of 
articulate  language.  Through  them  the  ears  are 
charmed,  the  understanding  perceives  and  interprets, 
according  to  conventional  methods,  articulate  vocal 
sounds,  and  the  human  personality  thrown  into  emotion 
vibrates  externally,  and  expresses  itself  in  regularly 
co-ordinated  vocal  sounds. 

They  are  collected  at  the  periphery  of  the  acoustic 
sensorial  plexuses,  and,  like  their  fellows,  are  condensed 
in  special  ganglia  of  the  grey  substance  of  the  posterior 
regions  of  the  optic  thalamus,  and  thence  radiated,  prin- 
cipally into  the  posterior  regions  of  the  cortical  sub- 
stance, which,  in  the  human  species,  present  such  a 
characteristic  development.  According  to  Wundt,  they 
are  the  impressions  most  rapidly  transmitted  to  the 
perceptive  centre. 

Like  their  fellows,  they  have  a  double  range;  they 
enter  into  relation  successively  with  the  psychic  sphere 
and  the  intellectual  sphere  proper,  and  in  these  tv\o 
regions  of  nervous  activity  they  excite  specific  reactions 
of  the  same  nature  as  their  fellows  do. 

I.  When  dispersed  in  the  plexuses  of  the  sensorinm 
they  at  first  develop  there  the  same  reactions  of  plea- 
.sure  and  pain  that  we  have  seen  succeed  each  other  in 


EVOLUTION   OF   SENSORIAL  IMPRESSIONS.        27 1 

cunsequence  of  the  arrival  of  sensitive  and  optic  im- 
pressions, according  to  the  same  physiological  processes. 
The  variable  condition  of  impressionability  of  the  peri- 
pheral regions  is  always  transmitted  into  the  central 
regions,  and  there  excites  concordant  emotional  states. 
When  the  ears  are  charmed,  the  sensorhim  is  similarly 
delighted,  and  inversely  when  the  ears  are  impressed 
with  a  certain  rhythm  and  with  certain  modulations 
into  flat  or  sharp  keys,  the  same  states  are  impressed 
upon  the  sensorium. 

Thus  it  is  that  grave  musical  sounds,  repeated  very 
slowly  and  in  a  chanting  manner — musical  phrases  in 
flat  keys,  and  andante — dispose  the  sensormm  to  reminis- 
cence, and  produce  in  us  a  special  condition  which 
constitutes  sorrow ;  and  that,  inversely,  loud  music, 
consisting  of  rapid  notes,  and  allegro  in  tempo,  or  airs  in 
■|-time  and  tricked  out  with  sharps,  awakes  emotions  of 
an  entirely  different  nature,  predisposing  the  heart  to 
gaiety  and  mirth,  and  inviting  us  to  dance  spontaneously 
and  move  our  limbs  to  its  cadence. 

Between  these  two  limits  of  profound  sorrow  and 
expansive  joy,  between  which  acoustic  impressions  cause 
our  natural  sensibility  to  oscillate,  there  is  a  whole 
series  of  intermediate  notes  which  may  be  successively 
set  in  vibration. 

Music,  indeed,  v;ith  its  infinite  number  of  tones,  is 
capable  of  impressing  us  in  various  manners,  and  deve- 
loping sensitive  conditions  very  distinctly  graduated.  It 
is,  like  spoken  language,  of  which  it  is  but  an  amplifica- 
tion, designed  to  form  a  sort  of  synthetic  language,  and 
to  join  the  train  of  the  cardinal  sentiments  which  are 
capable  of  causing  the  plexuses  of  the  human  sensorium 


272  THE   BRAIN   AND   ITS   FUNCTIONS. 

to  vibrate.  Thus  musical  sounds  now  express  tender 
sentiments,  flowing  forth  in  sweet  harmonious  notes, 
and  in  slow  time ;  while  in  other  circumstances,  with 
that  richness  of  expression  the  great  masters  have 
given  to  their  works,  we  see  a  melodious  phrase 
augmented  by  g^-aduated  accompaniments  become 
infinitely  complicated,  and  with  the  aid  of  powerful 
orchestration  symbolise  the  most  complex  sentiments, 
not  merely  of  man  considered  as  a  sentient  unit,  but 
even  of  man  considered  as  a  social  unit.  Thus  it  is 
that  the  great  masters  have  succeeded  in  expressing  in 
music  the  different  shades  of  human  sensibility,  just  as 
the  masters  of  painting  have  done  with  their  palette,* 
and  in  indelibly  imprinting  their  inmost  thoughts,  and 
the  sentiments  with  which  they  were  animated,  upon 
the  sensoriiim  of  those  who  comprehend  them. 

Acoustic  excitations,  associated  with  ail  the  special 
emotions  of  the  period  at  which  they  are  implanted 
in  the  sensoriiim,  thus  perpetuate  themselves  in  the  form 
of  memories  and  as  a  persistent  echo  of  the  past.  They 
are  thus  capable  of  reviving,  with  the  qualities  with 
which  they  were  previously  gifted.  Every  one  knows, 
indeed,  that  a  musical  phrase  is  sufficient  to  recall  the 
circumstances  in  which  we  heard  it  for  the  first  time  ; 
that  that  instantaneous  recollection  of  certain  airs 
heard  during  childhood,  which  is  often  so  vivid,  is 
capable  of  awakening  in  us  the  memory  of  the  places 
and  circumstances  in  which  they  were  first  heard  ;  and 
that   national  airs,   among  peoples  who  have  imbibed 

*  Tlius  Meyerbeer  has  succeeded  in  giving  a  musical  expression  to  the 
enthusiasms  of  politics  and  the  fanaticism  of  religious  strife,  in  his  grandiua*! 
scores  of  Les  Huguenots  and  Le  Prophete. 


EVOLUTION   OF  SENSORIAL   IMPRESSIONS.       273 

the  national  sentiment  in  a  precise  formula,  become  very 
aear  to  those  who  hear  them  when  far  from  their  coun- 
try, and  are  Hke  a  perfume  from  their  distant  home. 

2.  Besides  this  special  category  of  acoustic  impressions 
which  directly  address  the  smsoriiun,  there  is  another 
contingent  destined  to  play  a  most  important  part  in 
the  phenomena  of  cerebral  life — that  which  directly 
serves  for  the  manifestations  of  verbal  expression. 

In  the  first  phases  of  the  development  of  the  young 
child,  it  is  indeed  acoustic  impressions  that  first  awaken 
his  mind,  and  lead  him  to  reproduce  the  sounds  that 
strike  his  ears.  They  are  stored  up  in  his  sen- 
soriiLin  as  persistent  memories,  represent  the  absent 
objects  that  have  been  named  verbally  in  his  presence, 
and  when  reproduced  by  a  reflex  action  of  his  brain, 
become  the  natural  excitants  of  the  different  phonetic 
expressions  by  the  aid  of  which  he  designates  the  same 
objects,  as  well  as  the  different  conditions  affecting  his 
sensibility.  It  is  by  means  of  this  series  of  acts  that 
human  speech,  the  natural  daughter  of  auditory  ex- 
citations, becomes  developed  in  us,  expresses  itself  out- 
wardly, and  manifests  through  precise  and  appropriate 
sounds  the  emotions  of  the  sentient  personality  which  is 
in  action. 

It  amplifies  and  develops  little  by  little,  and  becomes 
in  course  of  time  a  true  vital  force,  capable  of  acting 
at  a  distance  like  a  charged  electric  machine,  and  of 
discharging  upon  the  sensoriinn  of  another  person,  and 
modifying  by  its  seductive  influence  his  sensibility  as 
well  as  his  intelligence.  By  virtue  of  the  energy  with 
which  it  is  projected,  and  the  heat  with  which  it  is 
expressed,  it  is  capable  of  provoking  difierent  emotion^ 


274  "iW^   BRAIN   AND   ITS  FUNCTIONS. 

at  a  distance  from  the  spot  where  it  was  engendered, 
and  of  exciting  sympathetic  and  persuasive  effluences 
which  induce  a  tacit  acquiescence  on  the  part  of  who- 
ever perceives  it.  It  thus  creates  a  sort  of  automatic 
consonance  between  the  orator  and  those  who  hear 
him,  and  becomes  the  bond  of  union  which  Hnks  us  to 
our  fellows.  It  is  always  due  to  it  that  men  speaking 
the  same  language  have  among  them  common  points  of 
contact,  by  which  their  sensor ia,  the  sensitive  regions  of 
their  whole  personality,  converse,  touch  each  other,  and 
vibrate  in  unison. 

3.  The  special  contingent  of  acoustic  excitations 
which  reverberates  in  the  purely  intellectual  regions, 
becomes  the  origin  of  a  series  of  appropriate  judgments 
which  we  form  respecting  the  timbre  and  intensity  of 
sounds  emanating  from  the  different  sonorous  bodies 
around  us. 

Thus  we  judge  of  the  specific  pitch  of  a  given  sound, 
by  dint  of  a  phenomenon  of  the  memory,  by  juxtaposing 
in  our  mind  the  reminiscence  of  a  past  sound  of  the 
same  nature  as  the  sound  that  now  strikes  our  ear. 

We  judge  of  the  intensity  of  a  sound-producing 
agency  by  the  manner  in  which  it  impresses  our  auditory 
nerves,  of  which  the  sensibility  is  called  into  play ;  and 
perhaps  the  notion  of  muscular  activity — the  work  ac- 
complished by  the  tensor  muscles  of  the  tympanum 
— may  play  a  certain  part  in  this  operation. 

It  is,  further,  by  a  reflex  effect  of  the  mind  and  the 
memory  that  we  arrive  at  a  judgment  respecting  the 
distance  of  a  sounding  body.  We  know  that  when  a 
known  sound  gradually  decreases  in  intensity,  it  is  be- 
cause the  sonorous  body  is  receding,  and  when,  on  the 


EVOLUTION   OF  SENSORIAL   IMPRESSIONS.       275 

contrary  it  gradually  increases,  it  is  because  the  sonor- 
ous body  is  approaching.  These  two  acquired  notions 
afford  materials  for  our  judgment  in  a  given  case.* 

Evolution  of  Olfactory  hnprcssions. — Olfactory  im- 
pressions, collected  from  the  peripheral  plexuses  of  tlie 
corresponding  nerves,  are  directly  transmitted,  as  we 
have  already  explained,  to  a  special  department  of  the 
optic  thalamus,  the  anterior  centre.  We  have  already 
insisted  upon  the  comparatively  large  volume  of  this 
sensorial  ganglion  in  those  vertebrates  that  present  a 
great  development  of  the  olfactory  nerves  ;  upon  the 
multiple  connections  it  effects  with  the  grey  substance  of 
\\\Q  septum  lucidum  and  mamillary  tubercles  ;  and,  finally, 
upon  the  indirect  relations  which  unite  it  to  the  regions 
of  the  sphenoidal  lobe,  and  in  particular  to  those  of  the 
grey  substance  of  the  hippocampus.f 

The  olfactory  nerves  transmit  to  the  sensoruini  the 
specific  and  unanalysable  notion  of  odours.  They 
communicate  to  it  at  the  same  time  a  special  coefficient 

*  When  the^e  relations  are  interrupted,  the  conscious  personality  easily 
accepts  the  change  and  allows  itself  to  be  hurried  into  strange  illusions.  It  is 
by  muffling  the  sounds  that  he  produces,  in  the  act  of  production,  that  a  ven- 
triloquist makes  his  audience  believe  that  the  sounds  so  produced  come  from  a 
distance.  It  is  by  means  of  the  same  mechanism  that  phantasmagoric  illusions 
in  the  domain  of  visual  impressions  make  us  think  that  an  image  which  grows 
larger  f.nd  larger  on  a  flat  surface  is  approachmg  us. 

f  The  multiplicity  of  the  paths  traver^ed  by  the  olfactory  impressions  in  pass- 
ing through  the  brain,  the  irregularities  and  individual  varieties  of  each  of  the 
stages  through  which  they  are  propagated,  must  exercise  an  influence  upon  their 
central  mode  of  elaboration.  It  is  perhaps  only  in  these  quite  special  con- 
ditions of  irregularity  in  the  transmission  of  olfactory  impressions  to  the 
sensorhim,  that  we  must  look  for  the  secret  of  those  individual  varieties  which 
we  so  frequently  observe  among  individuals  questioned  respecting  their  apprecia- 
tion of  odours.  Nothing  indeed  is  more  variable  than  the  testimony  of  each 
person  on  this  point.  Certain  odours  pleasant  to  some  people  oftend  the 
nostrils  of  their  fellows. 


2/6  THE   BRAIN   AND   ITS  FUNCTIONS, 

of  pleasantness  or  unpleasantness,  according  as  the  Inci- 
dent excitation  has  gratified  or  runcounter  to  their  natural 
sensibility.  For  this  special  group  of  nerves  the  impres- 
sion agreeably  felt  is  expressed  by  the  word  perfinne; 
the  impression  disagreeably  felt  by  the  word  stink.  These 
are  the  two  extreme  terms  between  which  all  the  shades 
of  their  peculiar  sensibility  are  developed.  They  aie 
incapable  of  penetrating  profoundly  into  the  recesses  of 
our  inner  sensibility,  to  excite  those  grand  movements 
of  expansion  or  depression  which  are  epitomised  in  the 
sentiments  of  joy  or  sorrow.  From  this  point  of  view 
they  are  very  inferior  to  optic  and  acoustic  impressions, 
which  monopolize  the  power  of  exciting  the  vibrations 
of  the  sensitive  chords  of  our  human  nature.  They 
only  excite,  then,  a  limited  action  of  the  sensoriiim  on 
their  arrival.  On  the  other  h^nd,  if  their  diffusive 
power  does  not  extend  to  the  emotional  sphere,  it  is 
reverberated  in  a  very  direct  manner  throughout  both  the 
vegetative  sphere  and  that  of  the  natural  sensibility  of 
certain  points  of  the  sensoriiLin,  and,  when  examined 
from  this  point  of  view,  olfactory  impressirjns  have 
reflex  effects  which  are  quite  unexpected. 

Thus,  we  all  know  that  certain  odorous  substances 
particularly  predispose  us  to  nausea ;  that  certain  ap- 
petising substances,  and  the  odour  of  preparations  made 
with  vinegar,  gum-dragon,  etc.,  act  upon  the  salivary 
secretion,  and,  as  we  say,  make  our  mouths  water ;  that 
perfumes  and  certain  specific  odours  have  an  aphrodisiac 
action ;  that  with  certain  impressionable  pen/ons  the 
presence  of  certain  odours  produces  profound  disturb- 
ances, sometimes  even  syncope  ;  that  finally,  in  certain 
persons  subject  to  headaches,  it  is  no  longer  the  sensoriuux 


EVOLUTION   OF   SENSORIAL  IMPRESSIONS.       277 

as  a  centre  of  reception  for  the  moral  sensibility  that  is 
affected  by  them,  but  the  sensitive  sensoriiim,  the  brain 
itself,  that  is  impressed  in  a  painful  manner,  in  certain 
of  its  histological  elements.  Many  persons  are  aware 
that  the  odour  of  certain  flowers  that  make  an  agreeable 
impression  on  their  sensorium  produces  a  painful  after- 
effect, as  though  they  had  to  do  with  a  physical  ache. 

Olfactory  excitations  are,  like  their  fellows,  capable 
of  being  stored  up  in  the  sensormm  in  the  form  of  per- 
sistent reminiscences,  and  of  being  associated  either 
with  visual  impressions  or  with  those  sensitive  impres- 
sions which  have  been  simultaneously  imprinted  upon 
us.  They  are  similarly  linked  with  our  ideas,  and  the 
sentiments  that  have  accompanied  their  genesis,  so  that 
the  chance  arrival  of  a  perfume  in  the  nostrils,  is  suffi- 
cient to  awake  a  whole  series  of  contemporary  memories, 
and  of  emotions  which  arise  in  consequence,  and  recall  to 
us  the  moment  and  the  place  in  which  the  perfume  was 
first  inhaled. 

Olfactory  impressions,  again,  furnish  the  intellect  with 
precise  and  specific  data,  which,  when  preserved  in  the 
form  of  reminiscences  and  compared  together,  become 
materials  by  means  of  which  we  fortify  certain  judg- 
ments. 

Thus  when  associated  with  their  fellows,  gustatory 
excitations,  which  they  perfect  and  complete  in  the 
act  of  deglutition,  they  furnish  us  with  precise  notions 
respecting  the  flavour  and  sapid  qualities  of  the  sub- 
stances we  are  eating. 

They  also  warn  us,  by  an  act  of  memory  and 
experience,  of  the  presence  of  foetid  emanations  float- 
ing in  the  air  or  in  the  liquids  we  absorb.     They  are 


278  THE  BRAIN   AND  ITS  FUNCTIONS. 

thus  like  advanced  guards  that  watch  incessantly  over 
the  security  of  the  operations  of  the  vegetative  life  of 
the  human  being. 

Evolution  of  Gustatory  Impressions. — Collected  on  the 
surface  of  the  buccal  and  lingual  mucous  membranes,  in 
the  terminal  expansions  of  the  glosso-pharyngeal  and 
lingual   nerves,  gustatory  impressions  are   thence  pro- 
bably distributed  within  a  definite  region  of  the  optic 
thalamus;    but  up  to   the  present  time,  we  are  not  in  a 
position    to    demonstrate    the   precise   place   of  their  con- 
densation.    From  this  point  they  are,   like   all   other  im- 
pressions, distributed    in    the    cerebral    cortex,  their   area 
of  distribution  here  also  not  being  yet  determined. 

I.  Intimately  connected  with  their  companion  olfac- 
tory impressions,  in  their  method  of  impressing  the  sen- 
sorium^  and  being  constantly  associated  with  them,  they 
owe  to  this  union  a  notable  portion  of  their  energy,  and 
the  various  forms  in  which  they  reveal  themselves  in  us. 
Thus  it  is  that  the  capacity  we  have  for  tasting  the  flav- 
our of  certain  sapid  substances,  such  as  the  bouquet  of 
some  wines,  is  only  the  combined  effect  of  olfactory  and 
gustative  impressions,  these  latter  being  quite  incapable 
of  producing  such  a  result,  as  we  may  assure  ourselves 
by  stopping  our  nostrils  and  allowing  our  gustatory  im- 
pressions to  act  alone.  We  then  perceive  how  restrained 
is  their  field  of  activity. 

They  give  us  the  unanalysable  and  specific  notion  of 
sweet,  saccharine,  salt,  acid,  acrid,  and  bitter  savours. 
The  diapason  of  tones  that  they  set  vibrating  in  the 
sensorium  is,  as  we  can  see,  by  no  means  rich  in  varied 
shades. 

2.  Genesis  of  the  Notion  of  Good  and  Evil. —  On  the 


EVOLUTION   OF   SENSORIAL  IMrRESSIONS.       279 

Other  hand,  they  present  this  very  characteristic  quahty, 
that  the  mode  in  which  their  extreme  notes  affect  the 
Stusoriiim  is  so  significant  and  so  typical  that  they  con- 
stitute for  it  two  quite  pecuHar  and  original  conditions, 
which  assist  us  in  judging  and  comparing  certain  pheno- 
mena of  the  moral  order. 

Thus,  when  the  natural  sensibility  of  our  gustatory 
nerves  has  been  gratified,  when  a  sapid  substance  has 
brought  them  into  a  pleasant  condition,  this  peculiar 
state  of  satisfaction  is  transmitted  to  the  se?isori?mt,  is 
there  propagated,  and  produces  an  analogous  condition  ; 
and  this  analogous  condition,  initiated  by  the  peripheral 
nerves,  becomes  a  subjective  notion,  the  notion  of  good- 
iic'ss — equivalent  to  the  notion  of  beaicty  excited  in  the 
saisoriiirn  by  the  optic  nerves  when  agreeably  impressed. 
We  say  then  that  a  thing  is  good  when  it  has  fully 
satisfied  our  gustatory  nerves ;  so  that  this  peculiar 
w^ord,  primarily  applied  to  the  agreeable  perception  of 
a  sapid  substance,  is  generalized  in  the  sensoriiim,  and 
becomes  a  moral  appreciation  which  we  unconsciously 
apply  to  a  whole  series  of  acts  of  the  human  activity. 
We  declare  them  ^^^^,  and  consider  them  2,^  good  actions, 
merely  because  they  have  produced  in  us,  in  the  emo- 
tional regions  of  our  moral  sensibility,  an  impression 
equivalent  tp  that  which  a  gustatory  impression  agree- 
ably perceived  determines  in  the  sensorium. 

Inversely,  bitter  substances,  which  cause  the  nerves  of 
taste  to  shrink,  produce  in  the  sensormm  a  disagreeable 
reverberation,  and  inevitably  become,  under  the  designa- 
tion of  bad  substances,  the  expression  of  a  painful  im- 
pression in  opposition  to  the  last,  and  equivalent  to  that 
of  pain  in  the  purely  sensitive  order  of  phenomena. 


280  THE  BRAIN   AND   ITS   FUNCTIONS. 

This  specific  notion  is  thus  susceptible  of  being  gene- 
rahzed,  of  becoming  subjective,  and  of  being  appHed  to 
the  appreciation  of  purely  moral  actions,  which  we  declare 
evily  tainted  with  wickedness,  because  they  have,  without 
our  knowledge,  developed  in  the  sensorium  a  painful  im- 
pression, equivalent  to  that  produced  by  a  disagreeable 
gustatory  impression. 

3.  Gustatory  impressions,  though  incapable  of  causing 
great  shocks  in  the  emotional  regions  of  our  personality, 
are,  like  their  companions,  olfactory  impressions,  capable 
of  radiating  into  the  different  regions  of  the  vegetative 
sphere;  they  are  both  of  them  fundamental  excitations 
of  this  special  division  of  cerebral  life. 

Thus  it  is  they  which  directly  regulate  the  functions 
of  the  stomach,  and  through  these  the  life  of  the 
organism.  Every  one  knows  what  a  state  of  erethism 
is  produced  in  the  gastric  mucous  membrane  by  sapid, 
appetizing  substances,  and  what  dulness  of  appetite  is 
produced  by  insipid  ones ;  the  good  appetite  produced 
by  the  former  having  a  direct  influence  upon  the 
harmony  of  the  psychic  and  intellectual  activity. 

Former  gustatory  excitations,  preserved  in  the 
sensormm  in  the  form  of  persistent  reminiscences,  are 
on  this  account  easily  evoked,  and  may  be  compared 
with  recent  ones.  They  are  likewise  capable  of  awaking 
old  memories,  contemporaneous  with  the  moments 
in  which  they  have  been  deposited  in  the  sensormm^ 
and  of  reviving  past  emotions  and  the  old  associations 
of  ideas  that  have  accompanied  their  genesis.  Thus 
the  taste  of  food,  wine,  or  a  liqueur,  recalls  to  us 
such  or  such  a  period  of  our  youth,  such  or  such  an 
episode  of  our  life,  such  or  such  an   incident  in  our 


EVOLUTION   OF  SENSORIAL  IMPRESSIONS.       28 1 

travels.  Thus  gustative  impressions,  like  all  theh 
fellows,  live  with  the  same  life  that  these  do,  and 
participate  in  the  same  processes  of  cerebral  activity. 
United  to  their  partners,  olfactory  impressions,  they 
have  a  truly  specific  and  penetrating  radiation,  which 
extends  at  once  into  the  domain  of  intellectual  activity 
and  that  of  purely  vegetative  life.  They  thus  become 
the  occasion  of  a  series  of  memories  and  comparisons, 
and  of  the  different  gastronomic  judgments  that  we 
form  respecting  the  degree  of  sapidness  of  food,  the 
pre-eminence  of  certain  vintages,  and  the  rules  respect- 
ing alimentary  hygiene.  They  become,  when  intel- 
ligently directed,  the  occasion  of  a  series  of  particular 
satisfactions  which  are  associated  with  all  others,  and, 
as  Brillat-Savarin  has  so  well  expressed  it,  outlive  all 
the  rest  to  console  us  for  their  loss. 

Evolution  of  Genital  Impressions. — Genital  excitations, 
as  regards  their  genesis,  their  passage  through  the 
nerv^ous  system,  and  their  diffusion  in  the  sensoriimiy 
present  the  most  remarkable  analogies  to  gustatory 
impressions,  of  which  they  are  to  some  extent  a  copy. 

Like  these,  they  have  no  nerves  of  special  sensation ; 
like  these  they  are  conducted  into  the  central  regions 
by  means  of  radicle-filaments  which  are  there  dispersed 
according  to  the  special  mode  of  distribution  of  the 
posterior  roots  of  general  sensibility ;  *  and  like  these 
they  are  distributed  to  the  substance  of  the  central  grey 
matter  of  the  optic  thalamus,  and  then  to  the  plexuses 

*  We  know  also,  that  in  their  centripetal  course  they  are  extended,  with  (he 
conductors  which  carry  them,  over  the  floor  of  the  fourth  ventricle,  and  that 
lesions  of  this  locality  are  apt  to  produce  erection,  as  in  those  who  are  l)ung. 

cSee  Luys  "  Recherches  sur  le  systeme  nerveux,"  pp.  340,  342. 

20 


282  THE  BRAIN  AND   ITS  FUNCTIONS. 

of  the  sensoriiim.  It  is,  however,  as  yet  impossible  to 
determine  precisely  either  the  special  nucleus  reserved 
for  them  in  the  optic  thalamus,  or  the  territory  where 
their  dissemination  amc  ng  the  plexuses  of  the  sensoritim 
is  effected. 

Finally,  like  gustatory  impressions,  they  are  inter- 
mittent and  subordinated  to  the  chance  arrival  of  the 
causes  that  determine  them  ;  and,  as  the  last  point 
of  analogy,  if  they  are  as  fugitive  they  compensate  for 
this  by  their  vividness,  their  intensity,  their  suddenness  ; 
by  the  profound  manner  in  which  they  affect  the  senso- 
riunts  and  by  the  ephemeral  character  of  their  mani- 
festations. 

Collected  principally  on  the  surface  of  the  plexuses 
of  the  genital  organs  which  are  so  rich  in  erectile 
papillae,  genital  excitations  present  at  the  moment  of 
their  genesis  (in  much  ampler  proportions)  that  special 
phase  of  erethism  common  to  all  their  fellow  excita- 
tions, when  the  sensorial  impression  radiating  from  the 
external  world  is  reverberated  in  the  sensitive  plexuses 
and  becomes  incarnate  in  the  organism. 

For  this  special  order  of  excitations  the  primordial 
period  of  erethism  which  incarnates  them  in  the 
organism,  instead  of  being  a  local  and  instantaneous 
phenomenon  like  those  of  general  sensibility,  or  vision, 
for  instance,  is  divided  into  successive  moments.  It  is 
effected  by  means  of  special  erectile  apparatuses,  which 
develop,  and  complete  it,  and  insensibly  lead  up  to  a 
condition  of  supreme  exaltation.  Once  the  external 
impression  is  incarnated  in  the  sensitive  plexuses,  once 
the  notion  of  physical  pleasure  is  developed  with  all  its 
conse-^uences,  it  ceases  to  be  itself,  through   dynamic 


EVOLUTION   OF  SENSORIAL   IMPRESSIONS.       283 

exhaustion,  sheer  fatigue  of  the  nerves,  as  we  have 
seen  the  retina  when  fatigued  becomes  insensible  to  the 
contemplation  of  certain  luminous  rays. 

The  process  of  physical  pleasure  undergoes,  then,  a 
series  of  phases  through  which  it  only  gradually 
arrives  at  its  complete  expansion. 

It  begins  locally,  in  the  peripheral  plexuses,  with  a 
period  of  extreme  erethism,  from  the  intimate  connection 
of  the  sexes,  through  the  mysterious  conjunctions  of  the 
apparatuses  of  organic  life  ;  it  is  at  the  same  time 
enriched  by  the  action  and  sympathetic  participation  of 
all  the  diffuse  sensibilities  of  the  organism  which  are 
thrown  into  agitation,  those  of  the  tactile  surfaces,  the 
hands,  the  lips,  which  all  combine  to  enhance  its  pri- 
mitive energy  ;  it  advances  towards  the  central  regions, 
as  a  true  synthesis  of  all  the  impressionable  ele- 
ments of  our  nature  in  vibration,  is  propagated 
through  the  whole  length  of  the  spinal  axis  by  means 
of  the  conducting  fibres  which  convey  it,  and,  after 
passing  through  its  final  stages  in  the  intermediate  grey 
regions  of  the  optic  thalamus,  it  is  dispersed  in  the 
different  zones  of  the  sensorium,  carrying  with  it  the 
shock  of  joy  and  satisfaction  which  intrinsically  charac- 
terizes it. 

Like  all  the  other  sensorial  impressions,  the  excita- 
tions of  physical  pleasure  affect  both  the  sphere  of 
psychical  activity  and  that  of  intellectual  activity 
proper. 

I.  The  excitations  of  physical  pleasure,  which,  as 
regards  the  living  being,  represent  the  fundamental 
elements  of  the  prime  function  which  has  for  its  end  the 
reproduction   of   the  species,   arrive   in   the    sensoriunt 


284  THE   BRAIN   AND   ITS  FUNCTIONS 

accompanied  by  an  enormous  contingent  of  sensations 
emanating  from  different  regions  simultaneously  in  a 
condition  of  erethism.  They  essentially  carry  with  them 
impressions  of  joy  and  happiness,  and  produce  like 
conditions  in  the  elements  of  the  seiisorhnn  ;  becoming 
during  the  period  of  puberty  a  dominant  note  which 
vibrates  above  all  the  rest,  which  gives  its  tone  to  all  our 
actions,  all  our  discourses  ;  and  which,  when  it  happens 
to  be  set  vibrating  with  special  intensity,  extinguishes 
all  the  rest  by  its  intensity  and  splendour. 

Psychic,  ideal  love,  and  physical  love  are,  then,  the 
ultimate  links  of  one  and  the  same  chain  of  which  the 
elements  are  uninterruptedly  connected.  It  is  a  regular 
physiological  process,  which  has  its  roots  in  the  intimate 
connection  of  the  sexes,  and  its  expansion  in  the  most 
elevated  regions  of  psycho-intellectual  activity.  In 
evolving  itself  throughout  the  organism,  it  thus  involves 
the  incidental  calling  into  play  of  all  the  apparatuses 
of  the  essential  life  of  the  livhig  creature,  and  their 
harmonious  co-operation. 

It  has,  then,  its  raison  d'etre  in  a  purely  physical  plea- 
surable excitation,  which  presides  over  its  origin  and 
marks  its  first  stage.  It  is  a  fleeting  and  transient 
desire,  which  is  born,  passes,  and  fades  away  as  soon 
as  the  physical  demands  for  pleasure  which  gave  it  birth 
are  appeased  ;  but  as  the  same  physical  needs  arise 
again,  through  the  necessary  laws  of  the  movement  of 
life  in  living  beings,  the  same  voluptuous  desires  simul- 
taneously arising  in  the  sensoriinn,  it  follows  that  the 
reiteration  of  the  same  physical  satisfactions  finally 
leaves  upon  the  sensorium  itself  a  persistent  and  con- 
tinuous impression,  vibrnting  like  an  echo  of  the  past,  and 


EVOLUTION   OF   SENSORIAL  IMPRESSIO::S.       28$ 

thus  maintaining  a  durable  and  uninterrupted  sentiment. 
Thus  it  is  that  love,  a  sentiment  transient  and  ephemeral 
as  the  pleasure  which  gave  it  birth,  fixes  itself  perma- 
nently, and  lives  with  a  life  of  its  own.  The 
reiteration  of  the  satisfaction  of  physical  pleasure, 
obtained  from  the  same  sources  as  formerly,  and  new 
desires  resuscitate  and  reinvigorate  it,  and  become  the 
elements  of  its  continuity  and  its  persistence. 

Conjugal  love,  thus  made  an  abiding  sentiment  in  the 
sensoritnny  becomes  in  its  turn  the  physiological  pivot 
around  which  a  new  generation  of  consecutive  senti- 
ments gravitates. 

Thus,  by  the  natural  fact  of  the  evolution  of  the 
living  organism,  physical  love,  which  was  at  first  all 
concentrated  upon  a  single  head,  upon  the  being  which 
gave  it  birth — its  end  being  the  propagation  of  the 
species — when  once  this  end  is  attained  is  insensibly 
extended  to  the  offspring,  which  is  the  flesh  of  the  flesh 
of  this  being,  and  the  veritable  proliferation  of  her 
substance.  The  sentiments  of  the  family  which  are 
then  developed,  lead  man's  emotional  nature  into  the 
inevitable  cycle  of  the  affection  of  parents  for  their 
children,  that  inevitable  cycle  in  which  we  have  been 
preceded  by  all  the  generations  of  our  ancestors,  and  in 
which  all  the  representatives  of  the  human  race  are 
destined  perpetually  to  move. 

Here  the  process  of  physical  love  finds  its  last  stage, 
dying  out  of  itself  after  it  has  accomplished  its  work, 
by  developing  in  the  living  creature,  during  the  period 
of  his  maturity,  all  the  energies  of  his  organization, 
animating  his  heart  with  the  most  intense  emotions, 
inspiring  the  liveliest  sallies  of  his  intellect  and  imagi- 


2S6  THE   CRAIN   AND   ITS   FUNCTIONS. 

nation,  and  contributing  necessarily  to  the  perpetuation 
of  his  race  and  the  preservation  of  his  species. 

2.  In  the  domain  of  intellectual  activity  proper,  the 
excitations  of  physical  pleasure  have  an  action  as 
powerful  as  that  they  exercise  in  the  sphere  of  purely 
psychical  phenomena. 

In  proportion  as  the  human  being  who  has  passed 
through  the  transitory  phases  of  puberty  accomplishes 
his  physiological  evolution,  new  ideas  arise,  unappeased 
desires  are  awakened  ;  he  feels  himself  incomplete  in 
his  solitude,  and  comprehends  that  another  being  is 
designed  to  fill  the  void  of  his  sentiments  and  desires. 

Henceforth,  urged  on  by  his  latent  desires,  he  employs 
all  the  resources  of  his  intelligence  to  seek  out  his  future 
companion  and  to  prepare  for  her  the  necessary  material 
provision.  He  thinks  of  his  social  establishment;  he 
struggles  ardently  in  the  battle  of  life  :  the  woman,  and 
union  with  her  in  marriage,  are  the  secret  motives  of  his 
actions.  It  is  the  hope  of  attaining  this  end  that  sus- 
tains his  strength  and  maintains  his  courage  ;  and,  later 
on,  when  hie  has  attained  this  end,  he  still  struggles  (and 
puts  forth  all  his  intellectual  activity  in  the  struggle)  to 
save  his  offspring  from  the  troubles  of  the  road  along 
which  they  must  follow  him.  He  thinks  of  the  future, 
and  prepares  the  inheritance  he  will  leave  behind.  He 
thus  harmonizes  all  the  intellectual  activities,  all  the 
social  forces  he  can  command,  with  the  different  phases 
of  the  physiological  process  which  is  being  inevitably 
vv'crked  out  in  him  ;  and  under  the  most  diverse  forms, 
in  the  most  dissimilar  circumstances,  he  always  obeys 
the  same  necessary  laws  of  evolution  th^t  press  upon 
him  and  metamorphose  him  insensibly,  from  the  moment 


EVOLUTION   OF  SENSORIAL  IMPRESSIONS.       2S7 

in  which  he  becomes  a  candidate  for  marriage  to  that 
in  which,  after  having  been  a  husband  and  father,  he 
becomes  a  grandfather,  and  sees  in  the  second  genera- 
tion that  springs  up  around  him  the  secondary  ramifica- 
tions of  the  branches  of  which  he  is  the  parent  stem.  So 
that,  whatever  be  the  position  of  a  man  (I  mean  of  a 
complete  and  regularly  constituted  man),  on  whatever 
rung  of  the  social  ladder  we  may  imagine  him  placed, 
v/e  are  always  sure  to  find  at  the  bottom  of  his  actions, 
open  or  secret,  as  the  first  cause  of  their  motives,  the 
craving  for  physical  pleasure,  and  as  a  consequence, 
psychic  pleasure,  with  all  the  sentiments  to  which  it 
gives  birth.  It  is  this  which,  always  present,  always 
active,  becomes  in  every  act  of  his  life  the  natural 
stimulus  of  the  briskness  of  his  mind,  the  resources  of 
his  imagination,  and  the  vigour  with  which  he  enters 
upon  the  struggle  for  existence.  It  tinges  his  whole 
personality,  animates  him  incessantly,  and  produces 
such  concordant  action  of  all  his  powers  that  we  may 
say,  without  fear  of  mistake,  that  the  measure  of  his 
physical  is  also  that  of  his  moral  virility. 

3.  Genital  excitations  play  such  an  important  part  in 
the  sum  total  of  the  operations  of  psycho-intellectual 
life,  that  when  they 'are  arrested  in  their  development, 
in  consequence  of  certain  operations  that  nip  them  in 
the  bud  in  the  regions  where  they  have  their  point  of 
origin,  a  very  remarkable  effect  is  produced  upon  the 
intellect  and  character. 

Every  one  knows  how  mild  and  easy  castrated 
animals  are  to  manage,  and  how  this  fits  them  for 
the  rule  of  man,  through  the  modification  of  their 
natural  impetuosity.     In  man,  the  same  practice  pro- 


2u8  THE  BRAIN   AND   ITS   FUNCTIONS. 

duces  similar  effects.  According-  to  Godard,*  castration 
performed  on  the  adult  singularly  weakens  the  moral 
energy,  as  the  following  fact,  reported  by  d'Escayrac, 
de  Lauture,  proves.  "  I  have  seen,"  he  says,  "  six 
slaves  belonging  to  the  kachef  of  Abouharas,  in  Kor- 
dofan,  who,  in  consequence  of  a  conspiracy  against  the 
life  of  their  master,  were  emasculated  by  him.  All  were 
adults  at  the  time  of  this  mutilation,  and  none  of  them 
died.  Their  characters  changed  completely,  and  the 
submission  they  now  show  differs  remarkably  from  the 
spirit  of  rebellion  that  animated  them  previously." 

Godard  afterwards  addsf  that,  according  to  Dionis, 
castrated  persons  are  unsociable,  liars,  and  rascals,  and 
that  they  never  seem  to  practise  any  human  virtue  ;  and 
that,  according  to  Benoit  Mojou,  eunuchs  are  the  vilest 
class  of  the  human  race,  cowards  and  rascals  because 
they  are  weak,  envious  and  spiteful  because  they  are 
unhappy. 

Finally,  he  has  noticed  that  even  where  no  mutilation 
has  been  practised,  individuals  with  congenital  absence 
of  the  two  testicles  are  effeminate,  unenergetic,  timid  ; 
they  blush  easily,  everything  frightens  them,  and  it  is 
difficult  even  to  examine  t'lem  without  a  great  deal  of 
trouble. 

*  Godard,  "  Recherches  teratologiquesj  iur  I'appareii  s-^minal  dc  I'homrne,'' 
p.  68.     Paris,  i860. 
f  Loro  citifo,  p.  73. 


CHAPTER  III. 

THE    JUDGMENT. 

Judgment  is  the  principal  operation  of  cerebral 
activity,  by  means  of  which  the  human  personahty,  in 
presence  of  an  excitation  from  the  external  world, 
either  physical  or  moral,  expresses  its  condition. 

Among  the  diverse  operations  of  the  brain  in  action, 
that  of  judging  is  a  regular  physiological  process,  which 
is  developed  according  to  fixed  laws  and  inevitable 
organic  conditions,  and  which,  like  the  different  phe- 
nomena of  muscular  activity  (the  progression  of  the 
human  body  in  space,  for  instance),  expresses  life  in 
exercise  and  the  nervous  power  in  a  dynamic  state. 

The  action  of  judging,  so  far  as  it  is  a  physiological 
process  accomplished  by  means  of  the  cerebral  activities 
in  movement,  is  decomposable  into  three  phases,  which 
are  as  follows:  — 

1.  A  phase  of  incidence,  during  which  the  external 
excitation  impresses  the  sciisoriiivi  and  rouses  the  con- 
scious personality  to  action. 

2.  An  intermediate  phase  during  which  the  person- 
ality, seized  upon  and  impressed,  develops  its  latent 
capacities,  and  reacts  in  a  specific  manner. 

3.  A  final  phase  of  reflexion,  during  which  the  pro- 
cess, continuing  its  progress  through  the  cerebral  tissue, 


290  THE   BRAIN   AND   ITS   FUNCTIONS. 

is  projected  outwards  in  phonetic  or  written  co-ordinated 
manifestations.  The  impressed  human  personality,  in 
fact,  expresses  itself,  exhales  itself  in  its  entirety,  in 
either  articulate  or  written  language. 

I.  It  isvalways  a  recent  or  former  sensorial  impression 
that  naturally  excites  an  operation  of  the  judgment  and 
determines  its  action.  The  sensoidiim  is  impressed,  the 
human  personality  takes  part  in  the  phenomenon  ;  it  is 
strongly  affected,  and  reacts  immediately.  This  work 
of  absorption  of  the  sensorial  excitation  and  oi  conscious 
reaction,  on  the  part  of  the  personality,  implies  then  a 
series  of  connected  operations  which  follow  and  com- 
plete one  another,  like  the  different  phases  of  a  simple 
somatic  process.  It  even  requires  a  certain  appreciable 
time,  to  be  effected  in  the  cerebral  tissue,  and,  according 
to  the  nature  of  the  individual,  will  act  wuth  greater  or 
less  facility,  and  perfect  itself  with  exercise,  as  Bonders 
has  demonstrated.* 

*  Bonders,  by  means  of  very  ingenious  registering  instruments,  has  suc- 
ceeded in  introducing  a  precise  notation  in  studying  the  evolution  of  certain 
phenomena  of  the  cerebral  activity.  The  method  consists  in  making  an  impres- 
sion upon  a  person  and  noting  the  precise  instant  at  which  he  responds  to  it. 
'I  he  person  who  makes  the  experiment  must,  as  soon  as  the  impression  is  felt, 
press  with  his  finger  a  spring  which  sets  a  revolving  cyUnder  in  motion.  The 
number  of  revolutions  indicates  the  time  that  has  elapsed,  that  is  to  say  the 
time  necessary  to  permit  the  complete  process  of  the  judgment,  the  impregna- 
tion of  the  sensorium  and  its  expressed  reaction,  to  manifest  themselves 
externally.  The  precise  duration  of  voluntary  transmission  is  known,  smce  it 
is  always  pretty  much  the  same,  and  thus  we  arrive  at  the  knowledge  that  a 
luminous  sensation  is  more  quickly  perceived  than  an  acoustic  or  a  tactic.  In 
this  case  it  is  a  simple  thought  that  is  transmitted. 

Donders  again  applied  himself  to  ascertain  by  the  same  process  the  time 
n(?cessary  to  solve  a  dilemma.  A  person  is  in  darkness,  a  green  or  red  light  is 
flashed  upon  him,  and  he  is  to  make  a  certain  signal  with  the  right  or  left  han  1 
according  to  the  colour  exhibited.  The  sum  of  these  operations  is  more  com- 
plex and  requires  much  more  time;  but,  as  the  elements  of  the  previous  experi- 
ment are  here  ag.iiu  found,  we  have  only  to  deduct  the  time  necessary  for  this, 


THE  JUDGMENT.  29 1 

It  is  in  this  first  phase  of  the  operation  that  the 
whole  secret  of  its  final  rectitude  resides  ;  for  to  see  well 
and  to  judge  ivcll  are  synonymous,  and  to  acquire  the 
power  of  pronouncing  with  certainty,  respecting  such  or 
such  a  circumstance,  we  cannot  surround  ourselves  with 
too  many  precautions. 

Nothing,  in  fact,  is  more  difficult  than  to  have  a  clear 
and  precise  appreciation  of  real  things.  The  minute 
care  taken  by  physicists  and  chemists,  and  the  infinite 
precautions  with  which  they  surround  themselves,  in 
order  to  appreciate  simple  physical  phenomena,  show 
us  how  frequent  are  the  causes  of  error,  and  how 
liable  to  deception  is  all  observation  ;  since  we  so  often 
find  two  observers,  in  the  presence  of  the  same  physical 
and  palpable  phenomenon,  each  describing  it  in  his  own 
fashion,  and  each  giving  a  very  different  report  respect- 
ing it. 

A  fortiori  we  can  understand  that  when  we  have  to 
do  with  the  interpretation  of  complex  things,  to  form 
judgments  respecting  history,  contemporaneous  or  past ; 
respecting  the  facts  of  our  current  life,  in  which  all 
human  passions  are  openly  or  secretly  at  work  ;  respect- 
ing political  matters  ;  the  ascertainment  of  the  real  facts 
may  become  very  difficult,  the  very  notion  of  truth 
obscure.  We  see  how  those  judgments,  which  we 
succeed  in  formulating,  always  fail  at  some  point  or 
another,  from  the  intervention,  more  or  less  eager,  of 
c  ur  own  personality. 

(o  ascertain  the  time  required  by  the  brain  to  discern  whether  the  light  was 
green  or  red,  and  which  hand  was  to  be  used.  Donders,  "  Archives  need  in- 
daises,"  1867,  vol.  ii.  Instrument  for  measuring  the  time  necessary  for  psychi- 
cal acts. 


292  THE  BRAIN   AND   ITS   FUNCTIONS. 

2.  The  second  phase  of  the  process  is  no  less  delicate 
than  the  first ;  for  here  the  human  personality,  on  the 
advent  of  more  or  less  clearly  distinguishable  stimuli 
from  the  external  world,  comes  into  play  with  all  its 
sensibilities  awake,  reacting,  like  a  trustworthy  reagent, 
when  the  excitable  regions  of  its  inmost  core  have  been 
more  or  less  aftected. 

It  is  the  human  personality  that  feels,  that  is  moved, 
that  speaks  in  our  judgments,  and  that  reacts  in  an 
appropriate  manner,  according  as  it  is  restless,  impres- 
sionable, indifferent,  or  atonic  ;  reflecting  externally  in 
words  or  deeds,  the  infinite  varieties  of  feeling  that  lie 
maturing  in  its  recesses.  Like  a  true  leading-note, 
it  vibrates  every  instant  in  every  act  of  our  lives, 
and  gives  our  judgments  an  original  character  accord- 
ing to  the  key  in  which  it  is  pitched,  a  something  racy 
of  the  soil,  which  (when  once  our  ainoitr  propre  comes 
into  play,  and  our  own  personality  is  concerned)  always 
expresses  the  different  phases  through  which  our  senso- 
rium  passes  when  in  a  state  of  agitation. 

Hence,  the  difficulty  of  forming  impartial  judgments 
in  questions  of  the  moral  kind,  the  judges  being  biassed ; 
hence,  that  series  of  minute  precautions  taken  by 
legislators  at  every  step,  to  eliminate  interested  persons 
from  juries,  and  to  form  these  of  independent  indi- 
viduals free  from  all  prejudices.  Hence,  that  practical 
observation,  verified  by  every  day's  experience,  that 
young  and  ardent  natures  in  whom  the  effervescence  of 
the  sensorium  is  still  unabated,  are  apt  to  judge  of  men 
and  things  with  all  the  rapidity  and  prejudice  of  their 
characters  ;  and  that  the  judgment  is  exercised  in  a 
more   enlightened   manner  when   maturity  has  arrived, 


THE  JUDGMENT.  293 

aiid  the  wear  and  tear  of  life  have  exhausted  the  first 
ardours  of  the  natural  sensibility.  Cold  contemplation 
of  the  real  facts  is  more  easily  attained,  and  permits  the 
human  personality  to  expand  in  a  calmer  and  more 
reflecting  manner. 

It  is  therefore  in  this  intermediate  phase  of  its  evolu- 
tion, when  it  enters  into  contact  wath  the  human  persond 
-a'ity,  that  the  process  which  is  destined  to  be  converted 
into  judgment  comes  to  its  crisis,  according  to  the 
variable  emotivity  of  tlie  substratum  that  receives  it. 

When  the  phenomenon  is  produced,  two  circumstances 
may  occur  :  either  the  process  may  achieve  its  evolution, 
and  appear  externally  in  a  verbal  or  manuscript  formula 
which  epitomizes  it ;  or  it  may  die  out  on  the  spot,  re- 
main silent,  and,  like  a  living  force  which  undergoes 
transformation,  may  proceed  to  excite  secondary  impres- 
sions throughout  ihe  cerebral  regions  it  traverses.  New 
territories  of  affected  cells  will  then  come  into  play, 
and  according  to  their  automatic  activity  wnll  associate 
themselves  with  the  excitations  and  ideas  in  question. 
Thus  it  is  that  a  process  of  judgment,  suspended  in  its 
course,  becomes  the  local  origin  of  a  vibratory  move- 
ment which  radiates  to  a  distance  and  produces  secon- 
dary impressions.  It  is  because  of  this  physiological 
radiation  that  related  ideas  are  automatically  excited  ; 
that  new  views  arise,  manners  of  looking  at  the  matter 
not  at  first  dreamed  of;  and  that,  from  this  work  of 
internal  digestion  of  the  process  in  evolution,  a  whole 
series  of  new  considerations  springs  up  and  gives  to  the 
first  judgment  a  weight  it  had  not  before,  and  the 
natural  complements  of  its  real  value. 

The   process    of   juigment    has  then  for  its  special 


294  THE   BRAIN   AND  ITS   FUNCTIONS. 

characteristic,  according  as  it  advances,  the  privilefre  of 
extending  itself ;  of  determining  the  reaction  of  the  sur- 
rounding cerebral  elements ;  of  searching,  to  some  ex- 
tent, into  the  archives  of  the  past ;  of  associating  former 
notions  with  those  of  the  present ;  of  creating  partial 
local  judgments,  established  d  priori  as  results  of  the 
inner  experience  of  the  individual ;  and  of  permitting 
us,  at  a  given  moment,  to  juxtapose  and  agglomerate 
partial  judgments — to  agghUinate  them,  in  the  form  of 
arguments,  into  a  complete  judgment,  which  resumes 
them  all  in  a  true  synthesis. 

Thus,  for  instance,  when  I  auscultate  the  chest  of  a 
patient,  and  perceiving  the  existence  of  tubular  respira- 
tion, declare  that  the  patient  is  in  the  second  stage  of 
pneumonia,  I  give  utterance  to  a  judgment  that  has 
many  ramifications  in  my  mind,  and  is  made  up  of  a 
great  number  of  different  materials.  Starting  from  this 
blowing  noise  that  has  struck  my  ear,  I  represent  to 
myself  what,  under  similar  circumstances,  I  have  per- 
ceived on  previous  occasions.  I  have  observed,  for 
instance,  that  this  blowing  noise  corresponds  to  a 
hyperaimia  of  the  pulmonary  tissue,  with  concomitant 
induration,  that  it  depends  upon  an  induration  of  tissue, 
not  upon  the  presence  of  effused  fluid.  At  the  same 
time  I  perceive  with  my  eyes  the  general  condition  of 
the  patient,  I  note  his  countenance,  his  external  habit, 
the  state  of  his  tongue,  etc.,  and  a  new  series  of  notions 
acquired  by  the  exercise  of  optic  impressions  is 
awakened  in  my  mind  and  becomes  associated  with  the 
process  already  begun  by  the  auditory  impressions.  I 
percuss,  moreover;  I  feel  the  pulse;  I  palpate;  and  once 
more,  starting  from  a  new  series  of  sensorial  impres- 


THE  JUDGMENT.  295 

sions  that  come  into  play,  new  regions  of  the  scnsorium 
are  associated,  set  in  vibration,  and  take  their  part  in 
the  complex  operation  that  is  taking  place.  The  dif- 
ferent regions  of  my  brain  are  successively  affected. 
Notions  formerly  acquired  are  laid  under  contribution  ; 
they  come  forward  of  their  own  accord  on  the  occur- 
rence of  the  excitation  with  which  they  are  methodi- 
cally connected  as  contemporary  memories ;  and  thus  the 
personality,  reminded  of  the  primordial  impression, 
and  enlightened  by  the  total  product  of  the  related 
njtions  that  spring  up  automatically,  pronounces  its 
judgment  with  a  sufficient  number  of  materials,  and 
expresses  the  manner  in  which  it  is  effected  in  a  verbal 
form  which  is  the  index  of  its  present  condition.  Thus 
it  is  that  in  pronouncing  the  words  "pneumonia — second 
stage,"  I  epitomize  a  whole  series  of  former  notions, 
methodically  grouped,  which  have  made  their  appear- 
ance in  my  mind  viotu  propria. 

Natural  Predispositions. — In  this  second  phase  of  the 
cerebral  process,  which  is  being  accomplished,  the  human 
personality  is  seized  on,  as  we  have  said,  and  inevitably 
associated  in  its  evolution.  Here  a  new  peculiarity, 
which  occupies  an  important  place  in  the  phenomena  of 
cerebral  life,  comes  in  ;  viz.,  the  manner  in  which  that 
personality  is  brought  into  play  and  the  particular 
mode  in  which  the  sensorial  excitation  has  affected  it. 

We  have  already  insisted  (p.  43)  upon  the  curious  re- 
lations that  exist  between  the  different  provinces  of  the 
cortical  substance  and  certain  centres  of  the  optic 
thalami  with  which  they  are  more  particularly  con- 
nected. We  have  thus  shown  that  such  or  such  a  group 
of  sensorial  impressions  was  more  especially  distributed 


295  THE  BRAIN   AND   ITS  FUNCTIONS, 

to  such  or  such  a  region  of  the  cerebral  cortex  ;  and  we 
have  at  the  same  time  made  it  clear  to  what  an  extent 
the  greater  or  less  richness  in  cells  of  such  or  such  a 
cerebral  region,  and  the  briskness  and  impressionabilit)' 
of  these  cells  themselves,  may  induce  certain  functional 
predominances,  and  become  the  natural  cause  of  certain 
dispositions  and  special  aptitudes  of  the  mind. 

in  applying  these  data  to  the  evolution  of  the  pro- 
cess of  the  judgment,  we  recognize  the  fact  that  if  the 
human  personality,  at  the  moment  it  begins  to  take 
part  in  this,  finds  in  one  of  the  regions  of  excitation  a 
greater  num^ber  of  nervous  elements  than  in  such  or 
such  another  ;  if  the  elements  are  more  impressionable, 
more  vivacious,  better  co-ordinated  in  their  internal 
mechanism,  it  will  be  on  this  account  more  strongly 
impressed,  and  provided  with  means  of  expression 
more  rich  and  more  abundant. 

Thus,  served  by  the  best  instruments,  it  will  react  in 
a  more  complete  manner  ;  will  do  what  others,  less 
richly  endowed,  could  not  do ;  will  see  better,  hear 
better,  taste  better,  smell  better,  etc.  It  is  by  means  of 
these  natural  conditions  of  organization  that  certain 
individuals  show  themselves  superior  to  others  as  re- 
gards the  operations  of  the  judgment,  in  the  direct 
ratio  of  the  superiority  of  their  cerebral  constitution. 

On  the  other  hand  it  is  notorious  that,  just  as  all  the 
sensorial  organs  are  not  gifted  with  the  same  energies 
in  all  individuals,  and  that  one  is  marvellously  gifted 
for  music,  another  for  drawing,  another  for  painting, 
etc.,  so  by  reason  of  that  pre-eminence  of  certain  impres- 
sions in  the  sejisoriuni,  which  constitutes  in  a  manner 
the  cerebral  temperament  of  the  individual,   it  results 


THE  JUDGMENT.  297 

that  in  the  total  of  mental  faculties  whatever  cerebral 
region  is  best  furnished,  will  be  the  privileged  region  in 
whatever  operations  of  the  judgment  are  the  best  and 
most  rapidly  accomplished.  Hence  will  also  arise 
partially  competent  judgments,  the  individual  being 
better  fitted  to  judge  pertinently  respecting  some  one 
particular  subject.  Hence,  according  to  our  individu- 
alities, those  striking  contrasts  of  which  we  daily  see  so 
many  examples,  where  we  meet  with  persons  who  judge 
soundly  respecting  some  subject  they  have  thoroughly 
studied,  or  which  is  their  "hobby,"  who  are  yet  com- 
pletely incapable  of  forming  an  ordinary  judgment  re- 
specting a  simple  question  of  everyday  life.  The 
human  mind,  limited  in  its  resources,  and  the  tributary 
of  the  nervous  elements  through  whose  instrumentality 
it  manifests  itself,  is  only  capable  of  isolated  and 
restrained  efforts  ;  and  thus  it  is  that  in  the  infinite 
variety  of  its  manifestations  we  see  what  a  division  of 
labour  man  must  adopt  to  concentrate  his  energies  upon 
a  point  so  as  to  bring  them  to  bear  with  regularity,  and, 
in  a  word,  how  truly  judgment  is  said  to  be  a  most 
difhcult  operation  — -judicmin  difficile.^- 

3.  The  process  of  judgment,  when  once  it  has  called 

•  It  is  strange  to  observe  how  often,  within  pathological  limits,  we  meet  with 
individuals  who  partially  preserve  their  capacity  for  judging  of  certain  things. 
We  see  in  fact  lunatics  who  can  sustain  a  connected  conversation,  provided 
that  those  points  which  bring  their  personality  into  play  be  avoided.  If 
we  accidentally  touch  the  sensitive  chord  the  dissonance  suddenly  bursts  out 
and  the  delirious  conception  becomes  clear.  There  are  others  who  are  com- 
pletely incapable  of  judging  of  things  around  them,  of  acting  with  discern- 
ment where  their  own  interests  are  concerned,  and  who  notwithstanding  pre- 
serve an  aptitude  for  certain  games,  which  require  that  the  attention  shall  be 
sustained  over  a  Umited  field,  the  game  of  draughts,  for  instance,  which 
demands  the  contemplation  of  the  draughtboard,  witliout  necessitating  efforts 
Ot  memory,  as  games  of  cards  do. 

21 


298  THE  BRAIN  AND  ITS  FUNCTIONS. 

forth,  as  it  passes,  the  participation  of  the  different 
regions  of  the  cerebral  cortex,  and  has  associated  itself 
with  the  human  personality,  tends  more  and  more  to 
effect  its  extrinsic  manifestation,  and  to  express  itself 
outwardly  either  in  suitable  articulate  sounds,  by  which 
custom  has  taught  us  to  express  the  different  shades  of 
our  sensibility,  or  in  the  form  of  graphic  characters 
which  similarly  signify  our  ideas  and  inmost  thoughts. 

Henceforth  it  assumes  in  the  sensofium  the  form  of  a 
conscious  resolution,  and,  from  this  moment,  the  spon- 
taneous voluntary  act  is  similarly  completed  in  its  essen- 
tial elements  ;  since  the  cerebral  operation  in  which  it  is 
essentially  embodied,  the  awakening  of  the  human 
personality,  conscious  of  what  is  taking  place^  has 
occurred,  and  is  about  to  reveal  itself  externally  under 
the  most  diverse  forms.  From  this  moment  the 
process  of  judgm.ent,  in  its  third  phase,  belongs  to 
the  series  of  the  phenomena  of  voluntary  activity,  of 
which  it  marks  the  first  stage.  It  then  embodies  itself 
in  the  somatic  translation  of  a  voluntary  excitation  ra- 
diating from  the  psycho-intellectual  regions.  We  shall 
now  follow  it  in  this  last  phase,  by  explaining  the  action 
of  voluntary  motor-power. 

Community  and  Points  of  Contact  of  Human  Judg- 
ments.— Common  Sense. — Once,  now,  the  process  of  the 
judgment  has  been  externally  manifested,  and  by  this 
has  become  capable  of  implanting  itself  in  the  brain  of 
another  and  determining  in  him  similar  reactions, — 
once,  I  say,  this  operation  has  been  accomplished,  how 
is  it  possible  to  appreciate  exactly  the  value  of  the 
physiological  act  that  has  been  effected  }  How  can  we 
discern  the  justice  of  the  opinions  arrived  at,  and  know 


THE  JUDGMENT.  299 

whether  the  judgment  formulated  be  true  or  false,  and, 
as  we  say,  reasonable  or  unreasonable  ? 

When  dealing  with  the  discernment  of  things  which 
fall  immediately  within  the  domain  of  intellectual 
activity,  it  is  comparatively  easy  for  each  of  us  to  know 
that  a  judgment  pronounced  is  conformable  with  truth 
and  reason. 

Every  one  knows  that  in  the  domain  of  science,  all 
the  fundamental  truths  which  are  the  common  patrimony 
of  the  human  mind,  in  evolution  from  century  to 
century,  be  they  mathematical,  chemical,  physical  or 
biological,  are  universally  accepted  ;  that  what  is  true 
in  Paris  in  astronomy  is  similarly  true  in  Pekin  or  New 
York  ;  and  that  in  all  places  in  the  world,  wherever  they 
meet  with  a  sensible  and  well-informed  man,  they  are 
well-received  and  comprehended. 

Now  this  universal  concord,  this  acquiescence  of  all 
in  their  acceptance  as  legitimate  and  truthful  judgments, 
exists  because  they  only  express  evident  and  precise 
ideas,  verifiable  by  experience ;  because  every  one  can 
directly  or  indirectly  put  them  to  the  test ;  and  because 
the  human  personality  that  observed  and  expressed  them 
for  the  first  time  had  nothing  to  do  with  their  genesis, 
except  the  expressing  of  them  in  correct  and  appropriate 
terms,  the  emotional  regions  of  the  sensibility  not 
having  been  laid  under  contribution  in  the  smallest 
degree. 

The  real  only,  and  nothing  but  the  real,  is  revealed 
in  the  exposition  of  each  of  them  ;  and  the  indi- 
vidual who  has  expressed  them,  having  perceived  the 
external  world  in  an  incident  form,  has  but  reflected 
them  externally  without  adding  anything  of  his  own. 


3C0  THE  BRAIN   AND   ITS   FUNCTIONS, 

Thus,  when  Copernicus  or  Kepler  formulated  his 
laws  of  the  system  of  the  world  and  the  move- 
ments of  the  planets  ;  when  Newton  made  evident 
the  decomposition  of  light  into  its  elementary  rays; 
when  Lavoisier  demonstrated  the  part  played  by 
oxygen  in  the  phenomena  of  combustion  and  respira- 
tion ;  when  Laennec  furnished  his  contemporaries  with 
a  new  means  of  penetrating  with  the  ear  the  ma- 
chinery of  the  living  human  frame,  and  following  step 
by  step  the  respiratory  movements  and  those  of  the 
heart,— these  were  new  truths,  unexpected  judgments 
that  were  thrown  into  the  intellectual  domain,  and 
which,  as  a  correct  expression  of  reality,  and  certified 
as  conformable  to  this  by  every  one  interested,  were 
addressed  to  but  one  region  of  the  living  organism,  the 
intellectual,  without  being  addressed  to  the  emotional 
regions,  and  without  exciting  the  slightest  passion. 
These  are  palpable,  tangible,  verifiable  judgments,  which, 
being  addressed  to  all,  true  for  the  future  as  for  the 
present,  present  those  general  characters  proper  to  grand 
truths,  permanence  and  universality. 

If  it  be  generally  possible  to  appreciate  the  regularity 
of  a  process  of  the  judgment  in  the  sphere  of  purely 
intellectual  phenomena,  by  mediate  or  immediate  veri- 
fication, it,  on  the  contrary,  becomes  very  difficult 
when  we  have  to  judge  of  a  question  which  belongs  to 
the  class  of  moral  phenomena. 

Here  all  becomes  complicated  and  obscure ;  for  the 
criterion  of  verification,  experience,  which  we  had  before, 
is  here  wanting.  There  is  no  standard  by  which  to 
measure  the  things  of  the  moral  order ;  this  incident, 
fact,  or  particular  document  which  has  to  be  judged  of, 


THE  JUDGMENT.  3OI 

from  the  mere  fact  of  being"  a  direct  emanation  from 
some  one  else's  personality,  his  private  opinion  which  is 
externally  revealed,  borrows  from  the  emotional  regions 
whence  it  proceeds  a  specific  colouring  ;  his  private 
personality  is  more  or  less  at  work,  with  its  emotions 
and  passions. 

On  the  other  hand,  we  ourselves,  who  have  to  judge 
of  this  incident,  this  document,  these  words,  are  similarly 
unconsciously  affected  by  latent  sympathies  or  anti- 
pathies, which  make  us  see  and  judge  of  the  thing  under 
colours  which  are  not  always  those  of  reality. 

We  see,  then,  of  what  multiple  elements  the  action  of 
judging  of  a  phenomenon  of  the  moral  class  is  com- 
posed, and  how  many  unforeseen  factors,  variable  at  every 
instant  according  to  the  state  of  our  natural  sensibility, 
come  in  at  cross  purposes  to  drive  us  away  from  the 
desired  goal. 

Thus,  in  the  special  domain  in  which  moral  sensibility 
reigns  alone,  we  may  say  that  the  experimental  methods 
of  valuation  are  entirely  at  fault.  We  must,  therefore, 
have  recourse  to  entirely  new  methods,  considerations  of 
a  moral  kind  which  shall  serve  as  a  common  measure, 
and  which,  when  applied  to  the  valuation  of  phenomena 
of  the  same  nature,  may  be  capable  of  leading  us  to 
a  solution  of  the  problem,  and  the  formation  of  a 
judgment  respecting  its  nature. 

If  it  be  true,  indeed,  that  in  human  practice  and  the 
ordinary  affairs  of  everyday  life,  there  is  nothing  that 
differs  so  much  from  one  man  as  another  man  (since  we 
each  carry  in  us  the  weight  of  hereditary  influences,  in- 
fluences of  race  and  education  accumulated  throug[h  loner 
periods  of  time,  and  the  shades  of  .^sensibility  of  each  of 


302  THE   BRAIN   AND   ITS   FUNCTIONS. 

US  are  as  different  as  the  details  of  our  persons),  there  is, 
nevertheless,  in  that  sum  total  of  data  which  constitute 
the  elements  of  the  moral  life  of  man,  a  common  stock 
of  fundamental  truths  which  form,  as  it  were,  a  series  of 
moral  axioms  and  a  veritable  patrimony,  proper  to  all 
sentient  humanity.  In  all  times,  and  everywhere,  indeed, 
it  has  always  been  a  fine  thing  for  a  man  to  serve  his 
country,  to  sacrifice  himself  for  his  kind,  to  honour  his 
parents,  to  bring  up  his  family  well,  or,  to  make  use 
of  a  formula  which  contains  an  epitome  of  universal 
morality,  to  do  or  not  to  do  to  others  as  we  should  like 
others  to  do  or  not  to  do  to  us,  etc.  Within  a  more  re- 
strained circle  of  ideas,  we  know  that  in  unions  of  men 
ao-glomerated  into  isolated  societies,  though  they  be  in- 
dependent or  even  enemies,  there  is  a  common  fund  of 
ideas  and  sentiments.  Among  soldiers,  under  whatever 
flag  they  serve,  the  sentiment  of  military  honour  is 
always  the  same.  The  esprit  de  corps,  which  we  see  de- 
veloped in  certain  associations,  is  nothing  but  the  result- 
ant of  a  community  of  ideas  and  sentiments  among  all 
the  individuals  living  in  society,  and  united  by  the  bonds 
of  a  vast  confraternity. 

In  all  times  and  places,  then,  this  collection  of  com- 
mon ideas  and  sentiments  which  serves  as  a  basis  for 
phenomena  of  the  moral  order,  has  been,  as  it  were,  a 
sort  of  directing  clue  for  humanity,  a  magnetic  meridian 
of  common  sympathy,  by  which  men  have  unconsciously 
regulated  their  conduct ;  and  this  is  so  true,  this  common 
fund  of  moral  sensibility  is  so  inherent  in  our  natural 
sensibility,  in  our  very  personality  ;  it  is  so  vivid  in  us, 
and  so  organically  constituted,  that  wherever  we  find  one 
of  our  fellow-creatures  we  judge,  d  prioriy  that  he  must 


THE  JUDGMENT.  303 

vibrate  in  the  same  keys,  and  thrill  to  the  same 
impressions.  In  a  word,  we  believe  in  the  existence  of 
this  moral  sensibility  in  others,  with  the  same  certainty 
that  we  feel  regarding  the  existence  of  his  heart  that 
beats,  his  lungs  that  breathe,  and  his  limbs  that  move 
according  to  flexions  and  extensions  previously  deter- 
mined. 

This  common  basis  of  moral  sensibility  which  lives 
within  us  and  extends  to  all  our  fellow-creatures, 
forming  a  bond  of  universal  sympathy  between  all 
members  of  the  human  family,  thus  becomes  the 
veritable  criterion  and  touchstone  that  ser\^es  us  to 
appreciate  and  judge  of  the  value  of  a  phenomenon  of 
the  moral  kind.  To  a  particular  phenomenon  we  logi- 
cally apply  a  particular  method  of  diagnosis.  It  is  by 
taking  ourselves  as  a  term  of  comparison,  by  bringing 
our  conscious  personality  into  the  presence  of  the  actions 
of  another,  by  placing  ourselves  in  imagination  in  his 
place,  that  we  arrive  at  a  notion  of  their  scope,  and  a 
judgment  as  to  whether  they  are  conformable  to  the 
common  average-line  of  human  sentiments  and  universal 
sensibilit}'. 

We  thus  arrive  at  the  conclusion  that  there  are 
among  mankind  fundamental  truths  of  the  moral 
kind,  common  modes  of  feeling,  which  we  all  uncon- 
sciously obey,  and  which  constitute  the  common  line  of 
average^  the  cojnmon  sense,  according  to  which  the  great 
human  family  advances  along  the  path  of  life.  Each  of 
us  takes  the  bearing  of  his  acts  more  or  less  from  this, 
and,  if  these  deviate  from  it,  this  deviation  is  then  felt 
by  those  who  are  following  it,  and  they  accordingly 
judge  of  it  and  condemn   it,  as  a  deviation  from  the 


304  THE  BRAIN   AND   ITS  FUNCTIONS. 

common  law,  and  as  the  patent  expression  of  a  perturba- 
tion which  has  occurred  in  the  faculties  of  him  who  has 
thus  got  out  of  the  comm.on  rut. 

We  accordingly  consider  every  word,  and  every  piece 
of  writing  that  is  understood  and  accepted  by  all,  reason- 
able,  according  to  common  sense ;  while  on  the  other  hand, 
we  characterize  as  unreasonable  every  action  that  shocks 
the  notion  of  right  sense  and  rectitude  of  judgment,  as 
they  exist  in  others. 

Thus,  that  conception  of  things  in  their  totality, 
which  we  designate  under  the  term  reason,  is  gener- 
ally, from  a  physiological  point  of  view,  nothing  but  an 
abstract  synthetic  expression  which  serves  to  express 
that  unconscious  tendency  we  have  to  follow,  in  our 
lives,  our  ideas,  and  our  actions,  the  common  course 
followed  by  our  kind,  and  not  to  deviate  from  the 
meridian  line  followed  by  the  majority. 

Functional  Perturbations  of  Operations  of  the  Jndg- 
ment. — A  study  of  the  morbid  forms  of  the  operations 
of  the  judgment,  shows  us  how  closely  united  one  with 
another  are  the  different  phenomena  of  which  it  is  con- 
stituted, and  to  what  an  extent  the  whole  becomes 
perturbed  and  disordered,  when  one  of  these  comes  to 
be  disturbed  in  its  mode  of  action,  (especially  the  first, 
which  is  the  most  important,  and  the  point  of  departure 
of  the  operation  which  takes  place)  ;  and  how  far  the 
external  expression  which  results,  is  in  more  or  less 
complete  discord  with  the  reality  of  things. 

The  first  phase  corresponds,  as  we  have  said,  to  the 
moment  in  which  the  external  impression  penetrates 
the  sensorinm,  and  seizes  upon  the  personality,  which 
immediately  participates  in   the  communicated  impres- 


THE  JUDGMENT.  305 

sion.  This  is  the  delicate  moment  of  the  process,  when 
the  terms  of  the  problem  pre  stated.  Now,  what  hap- 
pens when  this  primordial  sensation  which  should  arrive 
at  the  sensorunn  with  the  maximum  of  precision,  and 
reflect,  in  as  exact  a  manner  as  possible,  the  surrounding 
phenomena,  is  incompletely  transmitted  and  falsified  ; 
when,  from  some  accidental  disturbance  in  the  different 
centripetal  apparatuses  charged  with  its  collection  and 
transmission  to  the  sensorimn^  it  arrives  there  deprived 
of  its  essential  character  and  incompletely  expressed 
(sensorial  illusions)  ?  What  happens  when,  on  the  other 
hand,  the  intermediate  regions,  whose  mission  it  is  to 
transmit  to  the  sensoriuut  peripheral  excitations  (centres 
of  the  optic  thalamus),  assume  a  condition  of  automatic 
erethism,  and  proceed,  motit  proprio^  to  launch  towards 
the  scnsor'ULin  subjective  excitations  engendered  on  the 
spot  (hallucinations)  ? 

The  human  personality,  then  without  any  means  of 
direct  control,  seized  upon  by  fictitious  autogenous  excita- 
tions, according  to  natural  processes,  accepts  the  change; 
receives  them,  absorbs  them,  works  them  up,  submits 
them  to  the  same, subtle  operations  as  though  they  were 
the  regular  and  legitimate  aliments  of  its  activity ;  and 
henceforward  the  abnormal  process,  by  means  of  the 
working  of  the  energies  proper  to  the  cerebral  elements, 
and  by  virtue  of  habits  formerly  acquired,  goes  on  of 
itself,  as  logically  and  inevitably  as  though  it  were  a 
pure  emanation  from  the  real  world  ;  of  course,  to  the 
great  stupefaction  of  persons  who  are  not  initiated  into 
the  knowledge  of  mental  diseases,  and  cannot  bring 
themselves  to  admit  that  a  false  conclusion  may  be 
deduced  with  perfect  logic,  and  that  logic  does  not  imply 


306  THE   BRAIN   AND   ITS   FUNCTION^. 

either  the  justice  or  the  precision  of  any  judgment  v/hat 
soever. 

Whether  the  protopathic  excitation,  then,  be  regularly 
or  irregularly  engendered,  all  goes  on  in  the  brain  auto- 
matically and,  to  some  extent,  unconsciously,  by  the 
individual  force  of  the  organs  traversed  by  the  process 
in  evolution  ;  as  though  we  had  to  do  with  a  simple 
reflex  operation  in  process  of  development  in  the  grey 
tissue  of  the  medulla ;  as  though  we  had  to  do  with 
a  foreign  body,  or  a  poisonous  substance  accidentally 
introduced  into  the  stomach,  and  inevitably  passing  on 
its  way  througn  the  successive  regions  of  the  intestinal 
canal. 

We  can  thus  comprehend  how  the  third  phase  of  the 
process  (which  is  but  the  ultimate  expression  of  the 
period  of  apparition  and  exteriorization  of  the  human 
personality,  which  manifests  its  peculiar  emotivity)  ex- 
presses, in  a  corresponding  manner,  the  different  vices 
of  organization  that  have  accompanied  the  first  moments 
of  its  genesis. 

In  fact,  if  we  study  the  concatenation  of  ideas  and 
arguments  in  the  case  of  the  most  rational  lunatics,  in 
those  who,  with  persuasive  logic,  express,  in  correct 
terms,  and  often  in  a  winning  and  convincing  manner, 
all  their  emotions  and  all  their  extravagant  conceptions  ; 
if  we  follow  out  with  care  the  natural  sequence  of  Yheir 
wanderings,  we  shall  always  find  that  the  first  origin  of 
their  arguments  and  recriminations,  their  ideas  of  those 
persecutions  of  which  they  accuse  those  who  surround 
them,  their  family,  society  in  general,  or  persons  un- 
defined, have  for  their  primary  point  of  departure, 
an  init'al  disturbance  occurring  in  the  method  of  .sen- 


THE  JUDGMENT.  307 

serial  perception,  and  in  the  initiatory  pliase  of  a  pro- 
cess of  judgment. 

It  is  always  a  sensorial  illusion,  an  hallucination,  that 
is  at  the  bottom  of  the  morbid  act,  and  directs  its 
inevitable  course. 

Thus,  we  sometimes  find  an  energetic  and  intelligent 
patient  affected  with  reasoning  mania,  who  bitterly 
complains  of  the  soiled  linen  that  is  given  him.  He 
violently  attacks  those  in  his  service,  and  complains  0/ 
the  tricks  of  which  he  is  the  victim  ;  then  shows  the 
linen  objected  to,  and,  lo  !  it  is  perfectly  clean.  We 
have  caught  the  sensorial  illusion  causing  the  extrava- 
gant judgment  in  the  moment  of  its  genesis.  The 
patient  imagined  that  he  saw  a  spot  of  dirt,  where  there 
was  none  ;  his  senses  used  him  badly  ;  and  hence  a  series 
of  extravagances  constantly  renewed  in  the  same  mind 
abused  by  its  senses,  and  recurring  by  means  oi  the 
same  mechanism. 

Or  again,  we  may  find  another  who,  also  suffering 
from  peripheral  disturbances  in  his  nervous  system — 
a  special  condition  of  his  gustatory  sensibility — con- 
cludes that  the  food  he  is  given  is  bad,  that  powders 
are  put  into  it,  that  they  wish  to  poison  him,  and  that 
such  and  such  a  person  is  guilty.  Another  has  scarcely 
risen  from  table,  when  he  makes  a  great  outcr}^,  be- 
cause, as  he  complains,  they  have  given  him  no  dinner. 
He  is  examined,  and  it  is  found  that  he  suffers  from  a 
temporary  anaesthesia  of  the  pharyngeal  mucous  mem- 
brane. 

A  laundress,  whose  case  is  reported  by  Charbeyron, 
and  v/ho  had  given  up  her  business  and  become  a 
sempstress   on   account    of    rheumatic   pains,   used   to 


308  THE   BRAIN   AND  ITS  FUNCTIONS. 

work  late  at  night,  and  got  ophthalmia.  She,  however, 
continued  to  work,  and  saw  at  the  same  time  four 
hands,  four  needles,  four  seams.  She  had,  in  fact, 
double  diplopia.  She  at  first  treated  this  as  an  halluci- 
nation ;  but,  at  the  end  of  some  days,  in  consequence  of 
weakness  and  prolonged  mental  anxiety,  she  imagined 
that  she  was  really  sewing  four  seams  at  once,  and  that 
God,  touched  by  her  misfortunes,  had  worked  a  miracle 
in  her  favour.*  As  we  see  here,  also,  there  was  a 
primary  disturbance  occurring  in  the  first  stage  of  the 
process  (a  sensorial  illusion,  diplopia)  determining  as 
its  consequence  the  extravagance  and  error  of  judg- 
ment. 

In  other  circumstances,  there  are  true  hallucina- 
tions, phenomena  engendered  on  the  spot  by  a  species 
of  erethism  of  the  sensorial  channels,  which  interpose 
and  produce  changes  in  the  conscious  personality. 
There  are,  in  fact,  almost  always  hallucinations  of 
hearing,  sight,  and  smell,  which,  either  isolatedly  or 
simultaneously,  impinge  upon  the  sensormm^  and  which 
are  almost  always  found  at  the  bottom  of  all  forms  of 
delirium.  Sometimes  there  are  voices  heard  subjectively, 
which  incite  the  person  under  hallucination  to  avoid 
such  or  such  a  person,  or  to  commit  such  or  such  an 
action  ;  that  speak  to  him  in  a  tone  of  menace  and 
trouble  him  in  his  nightly  rest.  Sometimes  there  are 
various  visions  which  keep  him  awake,  painful  per- 
ceptions, either  of  taste  or  smell,  which  cause  him  to 
refuse  food,  etc. 

Hence  an  indefinite  series  of  consecutive  judgments 

*  See  analogous  cases  cited  by  Parchappe,   "v^nnales    Medico- psychcl.," 
1861,  p.  271. 


THE  JUDGMENT.  3O9 

and  reflections,  varying  infinitely  according  to  the  nature 
of  the  soil  in  which  they  are  evolved  ;  hence  all  those 
forms  of  delirium  by  which  the  emotions  of  the  per- 
sonality reveal  themselves,  and  which  all  have  this 
common  basis  which  unites  thern  one  with  another, 
that  the  morbid  conception  implanted  in  the  mind  as 
a  homogeneous  element,  and  to  some  extent  as  a  con- 
ception contrary  to  nature,  only  reveals  itself  outwardly 
in  a  vague  and  cloudy  manner,  yet  logically,  notwith- 
standing. The  person  under  hallucination,  who  has 
vaguely  conceived  a  suspicion  in  consequence  of  a  low 
auditory  impression  which  has  affected  his  sensoriujji, 
outwardly  expresses  this  state  of  indecision  and  vague 
information  in  the  same  vague  manner ;  and  in  this  we 
still  find  the  ordinary  methods  according  to  which  the 
processes  of  the  judgment  manifest  themselves  in  us. 
The  person  under  hallucination  is  vague  in  his  expres- 
sions, because  the  impression  which  excites  his  per- 
sonality is  similarly  vague  and  confused.  He  does  not 
clearly  express  what  he  does  not  clearly  understand. 
He  uses  only  indistinct  formulae  to  express  the  con- 
ceptions that  pass  through  his  mind,  always  impersonal 
phrases  ; — someojie  has  told  him  so  and  so  ;  some  one  has 
warned  him  of  so  and  so ;  his  expressions  never  being 
descriptive  nor  vivid,  nor  possessed  of  those  distinct 
outlines  that  characterize  impressions  really  seen  and 
really  heard. 

Thus,  in  fine,  we  see  to  what  an  extent  the 
morbid  processes  of  divagation,  however  wide  apart 
be  the  diiferent  forms  they  assume,  obey  the  same 
c;-eneral  laws  as  the  regular  processes  of  the  judgment. 
They  pass  through  the  same  phases  in  their  operatioui 


310  THE  BRAIN  AND   ITS   FUNCTIONS. 

by  means  of  the  same  automatic  machinery  ;  they  follow 
logically  the  same  routes  ;  and  when  they  are  at  dis- 
cord with  reality,  when,  in  a  word,  their  operation  has 
failed,  it  is  because  it  was  badly  prepared  as  regards 
the  arrival  of  the  sensorial  impression,  and  because  the 
phenomena  of  perception  have  been  disturbed  in  their 
essential  connections.  The  human  personality,  carried 
away  into  this  fatal  cycle,  obeys  automatically,  and 
inevitably  becomes  involved  in  the  pathological  dis- 
orders that  occur  in  the  sensorium.  It  is  incapable  of 
resisting  the  strain  ;  and  when  it  comes  to  its  senses, 
and  the  disease  is  cured,  it  is  rather  owing  to  a  calming 
down  of  the  regions  primarily  affected,  than  to  any 
action  of  the  conscious  volition.  The  mental  condition 
improves  with  the  physical,  and  if  the  divagation  dis- 
appears, and  the  individual  ceases  to  be  delirious,  it  is 
less  by  a  spontaneous  effort  of  his  will,  by  virtue  ot 
which  he  abjures  his  false  convictions  and  yields  to  the 
judgment  of  others,  than  because  his  brain  becomes 
permeable  by  the  surrounding  reality,  and  because  he 
absorbs  sensorial  impressions,  and  elaborates  them  as 
the  generality  of  mankind  do. 

We  know,  indeed,  how  refractory  to  all  sane  reason 
are  men  with  false  ideas,  and  what  a 'waste  of  labour  it 
is  to  endeavour  to  treat  a  partially  delirious  individual 
by  means  of  logical  reasoning. 


BOOK    III. 

PHASE  OF  REFLECTION  OR  EMISSION  OF  THE 
PROCESSES  OF  CEREBRAL  ACTIVITY. 


Preparatory  Period.  Motor  Processes, —  In  the  state- 
ment we  have  just  made,  we  have  seen  that  the 
processes  of  cerebral  activity,  which  consist  first  of  all 
in  an  impression  upon  the  seiisoriitm  of  external  origin, 
resolve  themselves  into  various  reactions  on  the  part  of 
the  cerebral  apparatuses  which  are  roused  into  activity, 
and  into  a  sort  of  intra-cerebral  radiation  of  the  exci- 
ting movement. 

Now  this  impression,  which  has  arrived  in  the  form  of 
an  incident  excitation,  is  a  living  force  in  act  of  trans- 
formation ;  this  force  is  implanted  in  the  scnsormm  ;  it 
becomes  reinforced  and  concentrated  according  as  it 
is  evolved  ;  it  is  necessary  that  it  shall  still  continue  in 
motion,  and  that,  under  one  form  or  another,  it  shall 
pass  out  of  the  organism,  by  discharging  itself  upon 
other  organs  designed  to  serve  it  as  gates  of  exit. 

From  this  new  stand-point  we  shall  henceforward 
consider  the  phenomena  of  cerebral  activity,  at  the 
moment  in  which,  in  their  third  phase  of  evolution, 
they  finish   their   last    stage  and  reveal  themselves    in 


312  THE  BRAIN   AND   ITS   FUNCTIONS. 

various  reactions.  These,  however  varied  their  appear- 
ances, nevertheless  represent  in  the  external  world  the 
reverberation  of  a  former  sensorial  impression  emanating 
from  this  external  world. 

Once  upon  their  outward  course,  the  processes  of  cere- 
bral activity  take  two  different  routes,  according  to  the 
variable  conditions  of  receptivity  of  the  cerebral  medium 
in  which  they  are  developed,  the  nature  of  the  individual, 
and  his  manner  of  feeling. 

Thus  they  are  sometimes  reflected  towards  the 
different  departments  of  vegetative  life.  They  do  not 
make  their  exit  from  the  organism,  and  in  that  special 
sphere  they  produce  secondary  commotions  of  a  more 
or  less  apparent  kind  ;  their  reflection  takes  place.in  an 
entirely  automatic  manner,  and  in  spite  of  voluntary 
action  (return  shock  of  mental  emotions  upon  the 
physical  constitution). 

Sometimes,  on  the  contrary,  they  appear  externally, 
and  reveal  themselves  by  the  help  of  various  means  of 
expression — phonetic  sounds,  graphic  signs,  appropriate 
gestures.  The  external  sensorial  excitation,  radiating 
from  the  external  world  that  gave  it  birth,  is  in  this 
case  directly  returned  to  this  external  world. 


CHAPTER  I. 

REFLEXION   OF   MOTOR   PROCESSES   UPON   THE 
PHENOMENA  OF  VEGETATIVE  LIFE. 

In  the  first  series  of  facts,  when  the  excitations  derived 
from  the  external  world  are  not  directly  reflected  out- 
wards— when,  under  the  influence  of  one  cause  or  another, 
the  primary  impression  remains  confined  within  our  own 
organism,  it  dies  away  there,  and  the  reverberation  which 
results  extends  to  a  greater  or  lesser  distance.  The 
nervous  discharge  of  the  process,  arrested  in  its  course, 
reacts  upon  one  region  or  another  of  vegetative  life, 
and  this  depends  upon  the  closeness  of  the  sympathetic 
links  uniting  each  of  these  with  the  sensorhim. 

We  have  shown,  on  the  other  hand,  that  by  reason  of 
these  connections,  there  exist,  as  it  were,  incessantly 
permeable  natural  channels,  by  vVhich  the  impressions  of 
the  sensormin  may  at  any  moment  become  associated 
with  the  phenomena  of  vegetative  life,  and  reverberate 
throughout  the  whole  extent  of  the  life  of  the  viscera. 

The  result  of  this  arrangement  is  that  every  external 
excitation  arriving  in  the  sensoriiim  is  sympathetically 
felt  in  the  different  centres  of  visceral  life,  and  that  the 
slightest  excitations  that  wrinkle  the  surface  of  its 
plexuses,  as  well  as  the  shocks  that  overwhelm  it,  are 
sympathetically  propagated  into  such  or  such  a  depart- 

22 


314  THE  BRAIN   ANC    [TS  FUNCTIONS. 

ment  of  organic  life ;  now  here  and  now  there,  centri- 
fugal currents  arise  instantaneously,  and  carry  to  a 
distance  without  our  knowledge  or  voluntary  participa- 
tion, prolonged  reverberations  of  the  oscillations  of  the 
psycho-intellectual  sphere. 

We  all  know  what  an  effect  painful  emotions  have 
upon  the  phenomena  of  the  circulation  ;  how  the  heart 
palpitates  without  our  knowledge  when  our  emotions 
are  at  work  ;  how  apt  this  latent  over-excitement  is  to 
fatigue  the  vital  energy,  and  what  a  serious,  and  long  ago 
recognized  influence  mental  causes  have  as  regards  the 
genesis  of  its  organic  lesions  ;  how  susceptible  the  vaso- 
motor innervation  is  of  becoming  associated  with  our 
emotions  in  a  similar  manner ;  since  instantaneous 
paralysis  of  the  capillaries,  on  the  one  hand,  is  apt  to 
determine  those  sudden  blushes  which  by  showing  them- 
selves upon  our  faces  reveal  so  well,  in  spite  of  us, 
the  secrets  of  our  agitated  sensibility ;  while,  on  the 
other  hand,  their  spasmodic  contraction  excites  those 
instantaneous  pallors  which  as  directly  reflect  the  per- 
turbations that  traverse  our  sensorium. 

We  all  know,  moreover,  how  directly  the  digestive 
organs  are  associated  with  the  impressions  of  this  same 
sensorhnn.  The  stomach  in  particular  is  intimately 
connected  with  the  phenomena  of  cerebral  activity. 
Like  the  heart,  it  every  instant  experiences  the  return 
shock  of  our  emotions,  and  like  it,  becomes  the  bearer 
of  the  sins  of  our  general  sensibility.  Every  one 
knows  that  digestion  is  disturbed  by  mental  emotions  ; 
that  vomiting  frequently  accompanies  cerebral  disease  ; 
and  that  in  certain  localized  pains  of  the  sensoriziin 
(hemicrania),  when   too   strong   ^    external   excitation 


REFLEXION  OF  MOTOR  PROCESSES.  315 

evokes  its  sensibility,  the  discharge  of  the  sensoriiim  in 
erethism  takes  effect  upon  the  stomach,  which  to  some 
extent  serves  as  a  gate  of  exit  for  the  nervous  over- 
excitement  reflected  towards  the  organs  of  vegetative 
Ufe. 

We  all  know,  further,  how  intimate  is  the  association 
between  the  respiratory  organs  and  our  natural  emotions. 
Sighs,  spasms,  anxieties,  the  involuntary  laugh  which 
sometimes  bursts  out  in  so  unexpected  a  manner  at  the 
sight  of  a  person  who  laughs,  and  the  frown  which  shows 
itself  under  similar  circumstances,  are  also  co-ordinated 
external  revelations  that  follow  upon  an  incident  exci- 
tation carried  into  the  sensormm,  and  reverberated  to- 
wards the  organs  whose  business  it  is  to  carry  it  off 
externally. 

More  than  this — and  this  also  is  a  phenomenon  known 
to  us  all — in  certain  circumstances  our  muscles,  which 
are  usually  such  faithful  interpreters  of  our  wills,  escape 
from  the  regular  stimulation  of  the  conscious  personality, 
and  then,  under  the  influence  of  powerful  emotions, 
become  subject  to  invincible  excitations  radiated  from 
the  sensorium^  apd  act  like  treacherous  servants,  only 
in  obedience  to  the  instructions  of  an  irregular  power, 
and  manifest,  without  our  consent,  the  different  states 
through  which  our  inner  sensibility  is  passing.  It 
is  by  reason  of  this  substitution  that  our  gestures,  our 
movements,  our  attitudes,  our  physiognomy  become, 
without  our  knowledge,  living  expressions  of  the 
different  states  of  our  sensibility,  and  in  a  manner 
apparent  phenomena  by  which  the  phase  of  erethism 
of  certain  regions  of  the  sensoriiim  is  externally  dis- 
charged.    In  these  cases  our  muscles  of  expression  are 


316  THE  BRAIN   AND   ITS   FUNCTIONS. 

grouped  ai.'.d  harmonized  in  a  co-ordinated  manner,  so 
automatically  and  so  unconsciously  that  we  see,  for 
instance,  those  of  the  iris  dilate  and  contract  alternately, 
and  express  by  their  play,  as  automatic  as  unconscious, 
the  different  modes  of  sensibility  of  the  retina  which  it  is 
their  business  to  protect. 

We  may  say,  then,  in  a  general  manner,  that  none  of 
the  peripheral  excitations  that  arrive  at  the  sensorium 
in  the  form  of  a  vibratoiy  impression,  of  a  living  force 
in  activity,  remain  there  stationary,  stored  up  in  one 
place.  They  develop  there  a  series  of  secondary  reac- 
tions, of  energies  regularly  co-ordinated,  which  are  inces- 
santly distributed  in  the  direction  of  the  apparatuses  of 
organic  life,  and  represent  the  continuity  of  the  primary 
movement,  and,  as  it  were,  the  modes  of  excretion  ot 
the  living  forces  implanted  in  the  organism,  which  here 
and  there  effect  their  physiological  discharge. 

Extrinsic  Manifestations  of  Cerebral  Processes.  Genesis 
of  the  Will. — The  processes  of  cerebral  activity  which 
reveal  themselves  externally,  and  make  their  exit  from 
the  organism  in  the  form  of  voluntary  conscious  manifes- 
tations, must  be  considered  successively  in  the  two  prin- 
cipal phases  of  their  evolution  : 

1.  In  their  period  of  incubation,  when  the  process  of 
the  will  is  still  only  constituted  by  a  purely  physical 
impression  ; 

2.  In  their  second  period  of  extrinsic  manifestation, 
when  they  take  form,  reveal  themselves  in  an  apparent 
manner,  and  lay  the  purely  motor  regions  of  the 
nervous  system  under  contribution. 

I.  In  its  preparatory  phase  of  incubation,  the  process 
of  the  will  is  nothing  but  the  riper  and  more  advanced 


REFLEXION   OF   MOTOR   PROCESSES.  317 

ultimate  period  of  an  anterior  operation  of  the  judg- 
ment, constituted  as  we  have  already  explained. 

The  human  personality  is  seized  upon  by  the  arrival 
of  the  excitation  emanating  from  the  external  v/orld. 
It  enters  into  participation  and  becomes  associated  with 
this  ;  and  from  this  intricate  connection  results  a  true 
intra-cerebral  automatic  radiation,  which  produces  the 
apparition  of  a  series  of  agglomerated  secondary  ideas. 
Rut  the  matter  does  not  stop  here  ;  this  inner  personality 
having  been  thus  seized  upon,  its  sensibility  having  been 
touched  in  any  manner  whatever,  has  reacted  by  virtue  of 
the  vital  forces  that  vibrate  in  it  in  a  latent  condition — 
it  has  been  affected  in  the  direction  of  its  most  profound 
affinities,  and  necessarily  this  reactionary  period  betrays 
itself  by  an  unconscious  desire  for  such  or  such  a  definite 
object,  and  by  a  repulsion  from  such  or  such  another. 

Desire,  attraction,  aversion,  repulsion,  are  therefore 
new  conditions  of  the  sensorium  which  necessarily  result 
in  the  natural  course  of  things,  and  which  thus  become 
the  primordial  elements  destined  to  constitute  a  process 
of  voluntary  activity. 

2.  The  psychic  operation  which  is  to  be  resolved  into 
an  act  of  will  is,  then,  in  itself  only  the  second  bar  of  a 
movement  already  begun.  It  is  only  the  regular  expres- 
sion of  the  human  personality,  seized  on,  and  impressed 
by  an  old  or  recent  excitation  from  the  external  world, 
and  carr>qng  back  to  the  external  world  the  different 
states  of  its  sensibility  in  emotion,  in  the  form  of  motor 
manifestations. 

Hence,  as  a  natural  consequence,  we  come  to  the 
conclusion  that  the  act  of  voluntary  motion  which  is 
developed    in    the   psychic   regions,  is   nothing   but   a 


3l8  THE   BRAIN   AND   ITS   FUNCTIONS. 

subordinate  fact,  a  secondary  phenomenon,  the  direct 
resultant  of  the  shock  of  the  sensibiHty  in  emotion  and 
the  spontaneous  reaction  of  the  sensorium.  Motor  power 
is  then,  physiologically,  nothing  but  sensibility  trans- 
formed. The  voluntary  excitation  comes  to  life  in 
that  subtle  process  in  which  the  impressed  human  per- 
sonality is  aroused.  From  this  reaction  of  the  sen- 
sibility it  emerges  as  a  natural  consequence,  like  a  vital 
force  in  evolution  ;  it  is  like  an  excito-motor  process 
radiating  from  the  sensitive  regions  of  the  spinal  axis 
towards  the  anterior  regions,  which  progresses  motic  pro- 
prio,  develops,  amplifies,  perfects  itself  infallibly  through 
the  whole  length  of  its  journey,  and  expands  in  its  last 
period  into  co-ordinated  motor  manifestations,  the  faith- 
ful dependents  of  the  sensitive  excitations  that  have 
given  it  birth. 


CHAPTER  n. 

TRUE  PERIOD  OF  EMISSION  OF  THE  PROCESSES  WHICH 
PRODUCE  VOLUNTARY  MOTION.  SPONTANEOUS 
REACTION  OF  THE  SENSORIUM.  MOTIVED  RESO- 
LUTION. 

Let  us  now  see  how  the  different  periods  of  voluntary 
activity  are  connected  one  with  another,  and  how  the 
physiological  operation  pursues  its  course. 

The  process  of  external  emission  of  the  emotivity  of 
the  sensorium  manifests  itself  externally,  sometimes  in  a 
rapid  and  instantaneous  manner,  sometimes  slowly,  pro- 
gressively, and  after  a  greater  or  less  period  of  time  ; 
this  extrinsic  revelation  taking  place  either  in  the  oral 
or  graphic  form,  or  in  the  shape  of  gestures  more  or  less 
expressive,  and  varied  attitudes. 

In  the  first  case,  when  the  voluntary  motor  phenome- 
non is  an  immediate  translation  of  external  impres- 
sions, the  human  personality,  aroused  and  vibrating, 
rapidly  responds  to  the  impressions  that  affect  it.  It 
outwardly  expresses  itself  directly,  now  in  the  form  of 
connected  articulate  sounds,  which  are  appropriate 
answers  to  the  interrogations  that  excite  it,  now  in 
current  conversations,  in  injunctions  of  all  kinds, 
prolonged  discourses,  in  writings,  expressive  movements, 
etc.,  etc.     It  expends  the  stores  of  emotivity  that  are 


320  THE  BRAIN  AND   ITS   FUNCIIONS. 

vibrating  within  it,  and  thus  reflects  the  various  sen- 
sitive currents  that  have  set  it  vibrating. 

Sensibility,  therefore,  underlies  every  motor  act  of 
the  organism  ;  and  when  we  immediately  answer  to 
demands,  when  we  let  ourselves  act  upon  the  natural 
impulses  of  our  sensibility,  and,  as  it  is  called,  do 
things  on  the  spur  of  the  moment,  it  is  our  person- 
ality that  expands  spontaneously,  without  artifice  or 
premeditation.  It  reacts  with  its  native  and  even  frank 
characteristics,  as  though  we  had  to  do  with  physio- 
logical phenomena  in  natural  evolution  ;  for  in  these 
circumstances  our  words  express  our  sentiments  in  an 
off-hand  manner,  and  the  compromises  of  meditation, 
and  diplomatic  reflection  have  not  yet  crossed  our  path 
to  mask  our  natural  spontaneity. 

In  a  number  of  other  cases  the  discharge  does  not 
take  place  in  a  rapid  and  immediate  manner ;  there  is, 
as  it  were,  a  cold  maceration  of  the  incident  impression 
in  the  tissue  of  the  sensoriitm,  by  which  this  impression 
is  matured  and  modified  by  the  mere  action  of  the 
medium  in  which  it  remains. 

When,  in  fact,  we  have  to  reflect,  to  mature  a  project, 
before  coming  to  a  resolution,  the  primitive  idea,  the 
first  excitation,  in  arriving  in  the  sensorium  awakens  a 
crowd  of  related  reactions.  It  has  been  perceived  in 
the  form  of  sensorial  vibrations,  and  these  vibrations 
radiate  to  a  distance  into  the  dinerent  cell-territories. 
These  latter,  on  being  impressed,  excite  ^the  automatic 
activity  of  those  of  the  neighbourhood,  and  at  the  same 
time  arouse  related  ideas  and  associated  memories 
formerly  registered  ;  so  that  at  the  end  of  a  period  of 
sojourn  in  the  sensorium,  variable  according  to  individual 


PROCESSES  WHICH  PRODUCE  VOLUNTARY  MOTION.  32  I 

temperament,  this  primitive  impression  has  proliferated 
and  slowly  produced  effects  that  reverberate  to  a 
distance. 

More  than  this,  the  ideas  of  others,  In  the  form  of 
oral  counsels,  written  advice,  and  auditory  and  optic 
impressions  interpreted  by  the  intellect,  have  come  to 
join  in,  to  group  themselves  around  the  primary  excita- 
tion, and  add  a  new  weight  to  the  operation  in  process 
of  development. 

Those  reflections  which  either  proceed  from  ourselves, 
or  are  inspired  by  the  surrounding  medium,  are  then 
converted  into  agglomerated  motives  or  thoughts,  des- 
tined to  influence  the  direction  of  the  voluntary  process 
and  direct  its  route. 

Things  being  thus  disposed,  a  delicate  phase  occurs 
in  the  cerebral  operation  that  is  being  accomplished. 
The  motives  being  all  confronted  with  one  another, 
with  their  intrinsic  and  extrinsic  characters,  the  shades 
which  characterise  them,  their  relative  value,  what 
route  will  the  process  take  ?  Under  what  form  will 
it  reveal  itself ;  and  in  what  manner  will  the  conscious 
personality  pronounce  itself?* 


*  This  delicate  moment  of  the  operation,  by  virtue  of  which  the  sensorium, 
when  seized  upon,  reacts  spontaneously  and  carries  outwards  the  different  con- 
ditions of  its  impressed  sensibility,  does  not  occur  in  some  individuals  without 
certain  difficulties. 

There  are  a  great  many  persons,  indeed,  whose  hesitation  is  the  dominant 
note  of  their  character.  At  the  moment  of  making  a  resolution  they  dare  not 
decide,  but  turn  about  in  a  persistent  indecision,  and  remain  in  suspense  whea 
action  is  necessary.  In  more  pronounced  cases,  where  this  psychological  con- 
dition is  still  more  distinctly  marked,  we  find  individuals  thus  affected  recount- 
ing all  the  anxieties  that  besiege  them  when  they  are  on  the  point  of  coming  to 
a  decision.  They  hesitate,  tormented  by  a  series  of  uncertainties,  and  if  they 
have  to  speak  or  take  up  their  pen  to  affix  a  signature,  or  perform  any  spou- 


322  THE  BRAIN   AND   ITS   FUNCTIONS. 

On  this  point,  the  controversies  of  philosophers  and 
metaphysicians,  which  have  been  taking  place  from 
time  immemorial,  have  succeeded  in  arriving  at  but  one 
thing — the  expression  in  sonorous  language  of  their 
ignorance,  more  or  less  complete,  of  the  fundamental 
characters  of  psychical  life.  We  must,  indeed,  pene- 
trate into  the  inmost  essence  of  the  activity  of  cerebral 
life,  into  the  complex  phenomena  in  which  it  reveals 
itself,  to  arrive  at  a  comprehension  of  the  evolution  of 
any  voluntary  act  whatsoever,  and  the  natural  manner 
in  which  it  expresses  itself  through  the  organism. 

Little,  indeed,  as  we  may  reflect  upon  the  concatena- 
tion of  the  processes  of  cerebral  activity,  considered  as 
we  have  here  just  done,  we  cannot  help  arriving  at  the 
conclusion,  that  the  voluntary  act  is  in  itself  nothing 
but  the  reaction  of  the  sensibility  thrown  into  agitation  ; 
that  it  is  this  that  is  latent  in  all  voluntary  manifesta- 
tions ;  and  that  it  is  always  the  sensorium  that,  under 
forms  the  most  dissimilar  in  appearance,  reacts  and 
outwardly  betrays  the  inner  impressions  by  which  it  is 
excited. 

The  sensibility  is,  therefore,  always  in  agitation 
at  the  commencement  of  every  voluntary  act  deve- 
loped. It  becomes  erect,  and  excites  the  opera- 
tions of  judgment  and  reflexion.  It  is  always  present, 
always  in  vibration,  and  inspires  our  words,  our  acts,  our 

taneous  action,   they  remain   fixed,    immovable,  in   a    species  of  invincible 
apathy. 

These  different  states,  from  the  most  simple  to  the  most  pronounced  forms, 
are  evidently  only  the  effect  of  a  partial  or  permanent  weakening  of  the  mental 
energies,  through  which  the  elements  of  the  sensorium,  in  a  torpid  condition,  are 
incapable  of  rising  to  the  phase  of  erethism,  of  reacting,  and  of  leading  by  their 
own  vitality  the  process  in  evolution  in  the  regular  direction  it  should  follow. 


PROCESSES  WHICH  PRODUCE  VOLUNTARY  MOTION.   323 

writings  ;  and  whatever  be  the  power  of  the  motives 
calculated  to  attract  it  away  from  its  inner  inclina- 
tions, it  follows  its  preordained  desires  for  what  is 
suitable  to  it,  what  pleases  it,  and  shrinks  from  what  is 
repugnant  to  it.  Every  one,  as  we  say,  gives  Jiis  opinion, 
every  one  judges  according  to  the  manner  in  which  he  is 
impressed,  in  which  he  fais ;  and  sensibility,  the 
seeking  after  what  is  pleasant  to  each  of  us,  is,  under 
the  name  of  self-interest,  to  such  an  extent  the  true 
motive  force  of  all  human  actions,  that  we  may  con- 
stantly declare  that  it  is  always  this  that  directs  them, 
like  a  powerful  magnet,  and  inclines  them  in  this  way 
or  that.  All  this  takes  place  in  so  unconscious  and 
certain  a  manner,  that  in  dealing  with  a  crime,  or  any 
guilty  action,  justice,  a  priori,  ascribes  responsibility  to 
those  who  may  have  had  an  interest  in  committing  it, 
by  obtaining  some  profit  from  its  perpetration. 

On  the  other  hand,  since  human  sensibility  is  in  itself 
one  of  the  most  mobile  of  things,  and  as  regards  this 
every  one  takes  his  pleasure  as  he  finds  it,  it  results 
that  the  manifestations  of  sensibility  will  vary  infinitely 
according  to  individuals,  and  will  sometimes  assume 
paradoxical  foi-ms  outside  of  the  usual  modes  of 
common  sensibility.  But  at  bottom,  although  the  sen- 
timents of  egotism  and  personal  satisfaction  may 
apparently  be  masked,  the  manifestations  of  the  will 
will  always  demonstrate  their  derivation  from  the  same 
origin.  Everyone,  as  we  have  said,  has  his  mode  of 
feeling,  and  just  as  we  see  individuals  experience  satis- 
faction in  certain  enjoyments  which  they  alone  are 
capable  of  perceiving,  so  we  find  them  manifesting  these 
different   states    of   their  sensorium    in    eccentric   and 


524  THE   BRAIN  AND   ITS   FUNCTIONS. 

extravagant  forms.  Thus  it  is  that  the  enthusiasms  of 
generosity,  self-abnegation,  even  self-sacrifice,  are  but 
too  often  only  a  disguised  manifestation  of  egotism,  a 
mode  of  feeling,  sid  generis,  in  which  we  exchange  a 
physical  advantage  for  an  emotion  of  the  moral  kind. 

From  the  moment,  then,  in  which  the  personalily 
becomes  interested  in  the  realization  of  such  or  such  a 
desire,  the  moment  in  which,  as  we  say,  a  resolution  has 
been  taken  by  it,  this  physiological  condition  expresses 
itself  in  a  co-ordinated  manner,  according  to  processes 
which  have  been  acquired  by  habit  and  commenced  in 
infancy,  and  by  which  we  have  learnt  to  make  our  fellow- 
creatures  comprehend  by  means  of  a  special  vocabulary 
the  ideas  which  germinate  in  us,  the  desires  that  demand 
satisfaction,  and  our  private  aversions. 

Henceforward  the  mental  process  has  made  one 
more  step  in  the  intricacies  of  the  cortical  substance. 
It  opens  up  a  new  path,  that  of  the  motor  regions 
proper.  A  living  automatic  pianoforte  from  this 
moment  comes  into  play,  and  in  various  forms  ex- 
presses the  sensitive  keys  it  is  bound  to  interpret 
faithfully.  It  is  the  instrumental  part  of  our  organism 
that  vibrates,  and  the  process,  tending  more  and  more 
to  emerge  from  the  plexuses  of  the  cortical  substance, 
becomes  concentrated  within  certain  circumscribed 
limits,  in  certain  psycho-motor  regions,  and  hence,  in 
the  form  of  rapid  intermittent  stimulations,  effects  its 
discharge  directly  upon  the  dinerent  territories  of  the 
corpora  striata. 

Coficatenation  of  Vohtntary  Motor  Acts. — We  have  Just 
seen  how  the  voluntary  stimulus,  conceived  in  its  primary 
phase  of  elaboration,  in  the  substance  of  the  plexuses 


CONCATENATION  OF  VOLUNTARY  MOTOR  ACTS.      325 

of  the  sensoriuni,  as  a  condition  of  purely  psychical 
vibration,  was  constituted  by  a  series  of  multiple 
elements,  all  concurring  in  its  genesis  ;  how  it  became 
inevitably  united  with  a  previous  phenomenon  of  sensi- 
bility in  agitation ;  and  how,  like  a  living  force  in 
evolution,  it  tended  more  and  more  to  emerge  from  the 
regions  where  it  was  conceived. 

From  this  precise  moment  it  leaves  the  purely  psycho- 
motor regions  of  the  cortex,  in  the  form  of  transient 
and  rapid  stimulations  destined  to  be  converted  into 
articulate  sounds,  digital  movements,  or  expressive  ges- 
tures ;  and  it  proceeds,  by  help  of  the  special  white 
fibres  (cortico-striate  fibres),  to  different  territories  of 
the  corpus-striatum,  of  which  it  thus  excites  the  imme- 
diate activity.     (See  5,  ii,  16,  Fig.  6,  p.  61.) 

Here,  in  this  first  stage  of  its  outward  course,  it 
insensibly  loses  its  original  character  of  a  purely 
psychical  excitation,  to  incorporate  itself  more  and 
more  with  the  organism,  to  materialize  itself,  in  a  man- 
ner, and  increase  its  dynamic  power  by  the  addition 
of  a  new  nervous  element,  the  cerebellar  innervation, 
which,  in  the  condition  of  a  static  force  in  permanent 
tension,  is  incessantly  distributed  in  the  plexuses  of  the 
corpus  striatum. 

Thus  reinforced  by  this  adventitious  contingent  of 
innervation  which  is  engrafted  into  it,  it  continues  its 
centrifugal  course  (see  7,  12,  19,  Fig.  6,  p.  61),  and  by 
means  of  the  antero-lateral  fibres  of  the  axis  (cerebral 
peduncles)  it  descends,  in  the  form  of  an  interrupted 
current,  to  excite  the  dynamic  activity  of  the  diff"erent 
motor  nuclei  of  the  spinal  axis,  which,  like  a  series  of 
a^^paratuses   always   ready  to   enter  into   action,  only 


326  THE  BRAIN   AND   ITS   FUNCTIONS. 

wait  its  arrival  to  develop  their  latent  activity.  From 
this  moment,  mixed  up  with  the  proper  activity  of  the 
different  spinal  regions,  it  projects  itself  along  the 
anterior  roots  and  thus  becomes,  in  its  final  phases  of 
transformation,  one  of  the  multiple  exciting  causes  of 
muscular  contractility. 

We  see  then,  to  sum  up,  from  what  precedes,  that 
the  processes  which  produce  voluntary  motion  pass,  in 
their  evolution,  through  phases  inverse  to  those  of 
the  processes  of  sensibility.  While  these  latter,  as  they 
approach  the  central  regions  of  the  sensormni,  are  puri- 
fied and  made  perfect,  becoming  more  and  more  intcl- 
lectualized  by  the  metabolic  action  of  the  different 
nervous  media  through  which  they  are  propagated ;  the 
former,  on  the  contrary,  conceived  as  psychical  vibra- 
tions at  the  moment  of  their  genesis,  amplify  and  are 
fnaterialized  more  and  more,  as  they  descend  from 
the  superior  regions.  They  become  complicated  by  the 
addition  of  adventitious  elements,  which  reinforce  them 
as  they  progress  (cerebellar  and  spinal  innervation),  and 
thus  become,  in  the  last  term  of  their  evolution,  a  true 
synthesis  of  agglomerated  dynamic  elements,  which 
resume  in  themselves  the  vital  forces  of  the  system 
through  which  they  have  been  developed — cerebral, 
cerebellar,  and  spinal  activities.* 

Conceived  under  this  simple  formula,  the  processes 
which  produce  voluntary  motion  begin  by  being  a  purely 
psychical  excitation,  and  insensibly  become,  by  the  natu- 
ral play  of  the  organic  machinery,  a  physical  excitation. 
In  thus  becoming  transformed  in  their  successive  evolu- 

*  See  Luys,  "  F.echerches  sur  le  systeme  nerveux  cerebro-spinal,"  p.  434. 
(Icoiiographie  photographique,  p.  71.) 


CONCATENATION  OF  VOLUNTARY  MOTOR  ACTS.     327 

tion,  they  present  the  fascinating  picture  we  constantly 
see  presented  to  us  in  the  working  of  steam-engines.  We 
see,  in  fact,  in  this  case,  how  a  force,  shght  at  its 
commencement,  is  capable  of  being  transformed,  and 
becoming  by  means  of  the  series  of  apparatuses  it  sets 
at  work,  the  occasion  of  a  gigantic  development  of 
mechanical  power. 

In  fact,  at  the  moment  when  the  engine  begins  to 
work,  a  very  slight  force,  the  mere  intervention  of 
the  hand  of  the  engine-driver  who  turns  a  handle 
and  lets  the  steam  rush  against  the  upper  surface  of 
the  piston,  would  suffice  for  this.  This  active  force, 
once  at  liberty,  immediately  develops  its  strength,  which 
is  proportional  to  the  surface  over  which  it  extends  ; 
the  piston  falls,  its  rod  draws  down  the  beam  ;  the  power 
is  developed  as  the  fly-wheel  revolves,  and  the  initial 
movement,  so  weak  at  its  commencement,  amplifies  and 
increases  continually,  in  proportion  as  the  volume  and 
power  of  the  mechanical  appliances  placed  at  its  disposal 
become  more  considerable  and  more  powerful. 

We  see  then,  in  conclusion,  after  an  examination  of 
all  the  details  of  cerebral  physiology  that  we  have  suc- 
cessively passed  in  review,  that  the  different  processes 
of  cerebral  activity  finally  resolve  themselves  into  a 
circular  movement  of  absorption  and  restitution  of 
forces.  The  external  world,  with  all  its  incitements, 
enters  into  us  by  the  channel  of  the  senses,  in  the  form 
of  sensorial  excitations  ;  and  the  same  external  world, 
modified,  and  refracted  by  its  intimate  contact  with  the 
living  tissues  it  has  traversed,  emerges  from  the  organism, 
and  is  reflected  outwards  in  the  various  manifestations 
of  voluntary  motor-power. 


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